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#1
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Setting up a two amp system
I am a newcomer and have a basic question. Hopefully someone can give
me a quick assist. I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. Thanks for any info. Scott D. |
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#2
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Setting up a two amp system
"Scott Dunam" wrote in message om... I am a newcomer and have a basic question. Hopefully someone can give me a quick assist. I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. Thanks for any info. Scott D. Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. |
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#3
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Setting up a two amp system
"Scott Dunam" wrote in message om... I am a newcomer and have a basic question. Hopefully someone can give me a quick assist. I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. Thanks for any info. Scott D. Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. |
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#4
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Setting up a two amp system
I want to set up a bi-amped system with an Adcom
545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. snip Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. Thanks for the information. I was operating under the idea that with each amplifier devoted to a channel there would be a cleaner sound, more power and less noise to each channel. I will look into bridging. Scott |
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#5
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Setting up a two amp system
I want to set up a bi-amped system with an Adcom
545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. snip Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. Thanks for the information. I was operating under the idea that with each amplifier devoted to a channel there would be a cleaner sound, more power and less noise to each channel. I will look into bridging. Scott |
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#7
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Setting up a two amp system
(Scott Dunam) wrote in
om: I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. snip Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. Thanks for the information. I was operating under the idea that with each amplifier devoted to a channel there would be a cleaner sound, more power and less noise to each channel. I will look into bridging. Scott Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. r -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#8
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Setting up a two amp system
"Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. |
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#9
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Setting up a two amp system
"Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. |
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#10
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Setting up a two amp system
"Arny Krueger" wrote in news:ioKdnWnrRfGBvASiRVn-
: "Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Arny, I am going to have to disagree with you on a few points. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. How one classes a range of frequencies is really not well defined AFAIC. In my speakers the midrange is an 8" driver, clearly a woofer for some people. Putting that aside you are stating that 200hz is midrange? Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. I don't think Roger is talking about midrange modulation at all. Here is what he says about the test equipment. "We also invest in some Bruel & Kjaer acoustic test equipment. Included in this is a 2305 chart recorder, 2607 measuring amplifier, 1022 oscillator and 2020 slave filter. The slave filter enables us to make continuous harmonic distortion measurements. This is very important in loudspeaker work. In electronics you can measure distortion at 20 Hz, 1kHz and 20kHz. If it's low you can accurately infer all frequencies in between are equally low. In speakers this is almost never true. Resonances and breakup can occur at any frequency and not show up at others. Shortly after that we add a B&K 1901 tracking frequency multiplier. This unit enables us to resolve the harmonic distortion measurements into continuous individual distortion curves--second, third, etc. This measurement technique is essential in the development of the LP/HP woofer by Carl Van Gelder in 1992." Nah, your argument doesn't hold up AFAIC. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. But does it? AFAIC subwoofers are not really part of the whole point I was trying to make. My point is that distortion is plainly audible in bass frequencies and as such, the statement that high distortion is permissible is incorrect. If you define bass as 0-200 hz that is your problem. The fact is that woofers typically extend much higher than 200hz and expecially the Vandersteen 1. The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. I am not sure what you are listening to Arny, but in my jazz and classical collection, one bass note played by itself is rare. Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. Ah, but acceptance is not the issue and it does not change the fact that the sound *is* different and that the distortion measurements do support those audible diffferences. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. The fact of the matter is unchanged Arny. The lower distortion in the woofers is plainly heard in the upper bass. Now if you wish to say that it isn't bass but midrange, fine. Whatever the woofer handles is what the woofer handles no matter what you or I class it as. When the distortion is as high at 10%, it can't help but be audible. I would be willing to bet that you could hear the difference plainly. One last point is that the original posting mentioned biamping Vandersteen I speakers. Unless my reasearch is faulty, that speaker is a 2 way system that uses a 1" tweeter and a 8" woofer. If driving that woofer with an amp that has high distortion products is not audible, I will buy you lunch, beer included. If you can prove it in my home, then I will buy you a 5 star dinner as well. Dinner will be complete with Dom and dessert! (:) r -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#11
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Setting up a two amp system
"Arny Krueger" wrote in news:ioKdnWnrRfGBvASiRVn-
: "Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Arny, I am going to have to disagree with you on a few points. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. How one classes a range of frequencies is really not well defined AFAIC. In my speakers the midrange is an 8" driver, clearly a woofer for some people. Putting that aside you are stating that 200hz is midrange? Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. I don't think Roger is talking about midrange modulation at all. Here is what he says about the test equipment. "We also invest in some Bruel & Kjaer acoustic test equipment. Included in this is a 2305 chart recorder, 2607 measuring amplifier, 1022 oscillator and 2020 slave filter. The slave filter enables us to make continuous harmonic distortion measurements. This is very important in loudspeaker work. In electronics you can measure distortion at 20 Hz, 1kHz and 20kHz. If it's low you can accurately infer all frequencies in between are equally low. In speakers this is almost never true. Resonances and breakup can occur at any frequency and not show up at others. Shortly after that we add a B&K 1901 tracking frequency multiplier. This unit enables us to resolve the harmonic distortion measurements into continuous individual distortion curves--second, third, etc. This measurement technique is essential in the development of the LP/HP woofer by Carl Van Gelder in 1992." Nah, your argument doesn't hold up AFAIC. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. But does it? AFAIC subwoofers are not really part of the whole point I was trying to make. My point is that distortion is plainly audible in bass frequencies and as such, the statement that high distortion is permissible is incorrect. If you define bass as 0-200 hz that is your problem. The fact is that woofers typically extend much higher than 200hz and expecially the Vandersteen 1. The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. I am not sure what you are listening to Arny, but in my jazz and classical collection, one bass note played by itself is rare. Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. Ah, but acceptance is not the issue and it does not change the fact that the sound *is* different and that the distortion measurements do support those audible diffferences. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. The fact of the matter is unchanged Arny. The lower distortion in the woofers is plainly heard in the upper bass. Now if you wish to say that it isn't bass but midrange, fine. Whatever the woofer handles is what the woofer handles no matter what you or I class it as. When the distortion is as high at 10%, it can't help but be audible. I would be willing to bet that you could hear the difference plainly. One last point is that the original posting mentioned biamping Vandersteen I speakers. Unless my reasearch is faulty, that speaker is a 2 way system that uses a 1" tweeter and a 8" woofer. If driving that woofer with an amp that has high distortion products is not audible, I will buy you lunch, beer included. If you can prove it in my home, then I will buy you a 5 star dinner as well. Dinner will be complete with Dom and dessert! (:) r -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#12
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Setting up a two amp system
"Robert Morein" wrote in message
... In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Although people have done this it doesn't hold up to the claims. High amperage designs are irrelevant. All you need is the appropriate current for a given power demand. If an amplifier can put out X number of watts that's all that is important from an amperage requirement. The woofer/midrange generally needs more power than the tweeter due to the spectral content of music but it's not that big a deal. Damping factor is also irrelevant. Damping factor essentially is the output impedance of the amplifier. High damping factor actually has less damping for the driver! In all but pathological cases the amplifier will not affect damping significantly since the primary damping contributors are the voice coil resistance, mechanical suspension and the air in the box. If you want low damping factor for whatever reason just stick a resistor in series with the speaker wire or use teeny, tiny speaker wire...it's the same thing. What's the point of having a "high amperage" design if you essentially stick a lossy element in series? Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. Since the loss from a passive crossover is minimal and there's a plethora of competent amps with adequate power it's a bunch of work for little, if any, gain. |
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#13
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Setting up a two amp system
"Robert Morein" wrote in message
... In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Although people have done this it doesn't hold up to the claims. High amperage designs are irrelevant. All you need is the appropriate current for a given power demand. If an amplifier can put out X number of watts that's all that is important from an amperage requirement. The woofer/midrange generally needs more power than the tweeter due to the spectral content of music but it's not that big a deal. Damping factor is also irrelevant. Damping factor essentially is the output impedance of the amplifier. High damping factor actually has less damping for the driver! In all but pathological cases the amplifier will not affect damping significantly since the primary damping contributors are the voice coil resistance, mechanical suspension and the air in the box. If you want low damping factor for whatever reason just stick a resistor in series with the speaker wire or use teeny, tiny speaker wire...it's the same thing. What's the point of having a "high amperage" design if you essentially stick a lossy element in series? Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. Since the loss from a passive crossover is minimal and there's a plethora of competent amps with adequate power it's a bunch of work for little, if any, gain. |
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#14
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Setting up a two amp system
"Rich Andrews" wrote in message
.44 "Arny Krueger" wrote in news:ioKdnWnrRfGBvASiRVn- : "Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Arny, I am going to have to disagree with you on a few points. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. How one classes a range of frequencies is really not well defined AFAIC. In my speakers the midrange is an 8" driver, clearly a woofer for some people. I explained how that is irrelevant. Putting that aside you are stating that 200 Hz is midrange? That's what I said, right? I said 200 Hz is lower midrange not bass. Remember, by octaves 640 Hz is the middle of the 20-20 KHz audio band. Middle C on a piano is 278.43 Hz. Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. I don't think Roger is talking about midrange modulation at all. Here is what he says about the test equipment. "We also invest in some Bruel & Kjaer acoustic test equipment. Included in this is a 2305 chart recorder, 2607 measuring amplifier, 1022 oscillator and 2020 slave filter. The slave filter enables us to make continuous harmonic distortion measurements. This is very important in loudspeaker work. In electronics you can measure distortion at 20 Hz, 1kHz and 20kHz. If it's low you can accurately infer all frequencies in between are equally low. In speakers this is almost never true. Resonances and breakup can occur at any frequency and not show up at others. Shortly after that we add a B&K 1901 tracking frequency multiplier. This unit enables us to resolve the harmonic distortion measurements into continuous individual distortion curves--second, third, etc. This measurement technique is essential in the development of the LP/HP woofer by Carl Van Gelder in 1992." I see no clear statement here at all about what he thinks is midrange or bass. Neither word appears anywhere in the paragraph, Nah, your argument doesn't hold up AFAIC. So far you've managed to ignore a simple clear statement that I made, and provide as proof a paragraph that does not contain the words midrange, bass or any known synonyms for them. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. But does it? AFAIC subwoofers are not really part of the whole point I was trying to make. My point is that distortion is plainly audible in bass frequencies and as such, the statement that high distortion is permissible is incorrect. I'll turn your first argument around on you. Slightly restated it becomes: How one classes a range of nonlinear distortion is really not well defined AFAIC. What is high distortion? If you define bass as 0-200 Hz that is your problem. The fact is that woofers typically extend much higher than 200 Hz and especially the Vandersteen 1. I explained that, but I guess I was wasting my breath, The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. I am not sure what you are listening to Arny, but in my jazz and classical collection, one bass note played by itself is rare. I explained that right below, but I guess I was wasting my breath, Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. Ah, but acceptance is not the issue and it does not change the fact that the sound *is* different and that the distortion measurements do support those audible differences. This begs the question what one considers to be high distortion. I have a number in mind - 10%. I think that anything more than 10% nonlinear distortion is high. However, I also know that large subwoofers with 10% distortion in their lowest octave are subjectively clean-sounding. Here's why. First off, a proper subwoofer does not produce midrange modulation distortion. Secondly, a subwoofer will produce harmonics that will add or subtract from harmonics that are already present in the music. No standard musical instrument produces absolutely pure tones. Bass tones often have more harmonics than fundamentals. At worst 10% nonlinear distortion will increase or decrease some single harmonic by no more than 1 dB. Below 100Hz you can't hear a difference when the level in an octave is increased or decreased by only 1 dB. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. The fact of the matter is unchanged Arny. The lower distortion in the woofers is plainly heard in the upper bass. I've explained why that is not necessarily so, twice. You have not rebutted the facts in either rendition. Now if you wish to say that it isn't bass but midrange, fine. Whatever the woofer handles is what the woofer handles no matter what you or I class it as. When the distortion is as high at 10%, it can't help but be audible. I just explained again why it can completely slip by the ear. I would be willing to bet that you could hear the difference plainly. Musical tones have a complex assortment of harmonics, particularly for low frequency fundamentals. Since there are already very strong harmonics in the music, there's a good chance of them masking harmonics created by nonlinear distortion in speakers and as I just showed, that masking can slip by the ear even if the distortion is like 10%. Difference tones created by harmonics tend to fall on top of other harmonics and be similarly masked. One last point is that the original posting mentioned biamping Vandersteen I speakers. Unless my research is faulty, that speaker is a 2 way system that uses a 1" tweeter and a 8" woofer. If driving that woofer with an amp that has high distortion products is not audible, I will buy you lunch, beer included. The amp would have to have low distortion except in the lowest octave, and somehow not intermodulate the midrange for this example to detract from my argument. I've never seen a decent amp that DIDN'T modulate the midrange when it clipped a full-range signal. This example is therefore irrelevant to what I've been talking about. If you can prove it in my home, then I will buy you a 5 star dinner as well. Dinner will be complete with Dom and dessert! (:) I have no interest in wasting my time with an irrelevant demonstration. Perhaps if you understood the difference, you would see the truth of my arguments and claims. |
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#15
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Setting up a two amp system
"Rich Andrews" wrote in message
.44 "Arny Krueger" wrote in news:ioKdnWnrRfGBvASiRVn- : "Rich Andrews" wrote in message .44... Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. I don't doubt it, but I see a need to be careful about which conclusions we draw from the available data. According to http://www.roger-russell.com/xr250.htm the XR250's crossover frequencies are 450 and 1300 Hz. That means that the woofer operates from 20 Hz to 450 Hz. I immediately observe that by most accounts the bass range does NOT go up to 400 Hz. 400 Hz is very definitely in the midrange. Arny, I am going to have to disagree with you on a few points. Yes, lots of loudspeaker systems reproduce 400 Hz with the woofer, but in those cases we usually say that the woofer is working up into the midrange. In my book bass is all over when you go up to 200 Hz. 200 Hz is lower midrange, not bass. How one classes a range of frequencies is really not well defined AFAIC. In my speakers the midrange is an 8" driver, clearly a woofer for some people. I explained how that is irrelevant. Putting that aside you are stating that 200 Hz is midrange? That's what I said, right? I said 200 Hz is lower midrange not bass. Remember, by octaves 640 Hz is the middle of the 20-20 KHz audio band. Middle C on a piano is 278.43 Hz. Secondly, Roger tips his hand when he starts talking about IM. It seems likely that he is talking about IM between frequencies below 100 Hz and frequencies above 200 Hz, maybe as high as 400 Hz. These are the sorts of frequencies that speaker designers use to test in cases like these. So, Roger is talking about bass modulating midrange which is of course a very serious problem when it happens. But let's call a spade a spade and not a hoe. I don't think Roger is talking about midrange modulation at all. Here is what he says about the test equipment. "We also invest in some Bruel & Kjaer acoustic test equipment. Included in this is a 2305 chart recorder, 2607 measuring amplifier, 1022 oscillator and 2020 slave filter. The slave filter enables us to make continuous harmonic distortion measurements. This is very important in loudspeaker work. In electronics you can measure distortion at 20 Hz, 1kHz and 20kHz. If it's low you can accurately infer all frequencies in between are equally low. In speakers this is almost never true. Resonances and breakup can occur at any frequency and not show up at others. Shortly after that we add a B&K 1901 tracking frequency multiplier. This unit enables us to resolve the harmonic distortion measurements into continuous individual distortion curves--second, third, etc. This measurement technique is essential in the development of the LP/HP woofer by Carl Van Gelder in 1992." I see no clear statement here at all about what he thinks is midrange or bass. Neither word appears anywhere in the paragraph, Nah, your argument doesn't hold up AFAIC. So far you've managed to ignore a simple clear statement that I made, and provide as proof a paragraph that does not contain the words midrange, bass or any known synonyms for them. Thirdly, most of the claims I've seen about "Higher distortion allowable in the bass frequencies..." related to subwoofers, which operate in the range of 10-120 Hz. Right away we can see that while the upper part of the subwoofer range overlaps with the lower end of the woofer range, 10-120 Hz is really quite a different range of frequencies than 20-400 Hz. There's no midrange at all in the 10-120 Hz range, and this turns out to be quite relevant. But does it? AFAIC subwoofers are not really part of the whole point I was trying to make. My point is that distortion is plainly audible in bass frequencies and as such, the statement that high distortion is permissible is incorrect. I'll turn your first argument around on you. Slightly restated it becomes: How one classes a range of nonlinear distortion is really not well defined AFAIC. What is high distortion? If you define bass as 0-200 Hz that is your problem. The fact is that woofers typically extend much higher than 200 Hz and especially the Vandersteen 1. I explained that, but I guess I was wasting my breath, The justification for the claim that "Higher distortion allowable in the bass frequencies" is that when bass is reproduced, the bass instrument is often a solo instrument, or instruments that are playing in close synchronization. Classic example of music with possibly problematical content in the 10-120 Hz range is the low pedals on a large pipe organ. At any rate, with solo sounds, intermodulation is largely irrelevant since only one sound is being played. I am not sure what you are listening to Arny, but in my jazz and classical collection, one bass note played by itself is rare. I explained that right below, but I guess I was wasting my breath, Another example is the combination of (up to) a piano, a bass, and bass drums. In the either case the bass note(s) are typically played in synchronization, so you don't have a situation where intermodulation is going to seriously disrupt the integrity of the sound being played in the sense that one note is not going to disrupt the continuity of another note that is being sustained. This contrasts with the situation where intermodulation is very problematical, and that is where one note in the midrange is being sustained, and it is audibly modulated by shorter bass notes that interject themselves at various points. The ear trains itself to the sustained sound, and when that sound's nature changes unexpectedly, the trained ear objects. In the case of solo sounds (even solo sounds that are composites of multiple instruments) the harmonic content is usually very high. It's not the least bit unlikely that one or more harmonics has more energy in it than the fundamental. In this context, nonlinear distortion causes a small shift in harmonic structure, which the ear seems to accept quite easily. Ah, but acceptance is not the issue and it does not change the fact that the sound *is* different and that the distortion measurements do support those audible differences. This begs the question what one considers to be high distortion. I have a number in mind - 10%. I think that anything more than 10% nonlinear distortion is high. However, I also know that large subwoofers with 10% distortion in their lowest octave are subjectively clean-sounding. Here's why. First off, a proper subwoofer does not produce midrange modulation distortion. Secondly, a subwoofer will produce harmonics that will add or subtract from harmonics that are already present in the music. No standard musical instrument produces absolutely pure tones. Bass tones often have more harmonics than fundamentals. At worst 10% nonlinear distortion will increase or decrease some single harmonic by no more than 1 dB. Below 100Hz you can't hear a difference when the level in an octave is increased or decreased by only 1 dB. In the other case, the fact that the midrange note(s) are being periodically intermodulated (AM of FM distortion or both) by a bass note is very audible, and for a number of reasons. One reason is the fact that the ear is a lot more sensitive to midrange than bass, and the bass note doing the intermodulation may not be as noticeable as the intermodulation that it causes. Of course the best situation is the situation where there is no audible nonlinear distortion. I'm not trying to justify equipment with nonlinear distortion as a rule. However, because of how they are used, it seems reasonable to set a higher threshold for concern about nonlinear distortion at the lowest frequencies in subwoofers. It also seems reasonable to be far less tolerant of nonlinear distortion in speakers that also reproduce midrange. The fact of the matter is unchanged Arny. The lower distortion in the woofers is plainly heard in the upper bass. I've explained why that is not necessarily so, twice. You have not rebutted the facts in either rendition. Now if you wish to say that it isn't bass but midrange, fine. Whatever the woofer handles is what the woofer handles no matter what you or I class it as. When the distortion is as high at 10%, it can't help but be audible. I just explained again why it can completely slip by the ear. I would be willing to bet that you could hear the difference plainly. Musical tones have a complex assortment of harmonics, particularly for low frequency fundamentals. Since there are already very strong harmonics in the music, there's a good chance of them masking harmonics created by nonlinear distortion in speakers and as I just showed, that masking can slip by the ear even if the distortion is like 10%. Difference tones created by harmonics tend to fall on top of other harmonics and be similarly masked. One last point is that the original posting mentioned biamping Vandersteen I speakers. Unless my research is faulty, that speaker is a 2 way system that uses a 1" tweeter and a 8" woofer. If driving that woofer with an amp that has high distortion products is not audible, I will buy you lunch, beer included. The amp would have to have low distortion except in the lowest octave, and somehow not intermodulate the midrange for this example to detract from my argument. I've never seen a decent amp that DIDN'T modulate the midrange when it clipped a full-range signal. This example is therefore irrelevant to what I've been talking about. If you can prove it in my home, then I will buy you a 5 star dinner as well. Dinner will be complete with Dom and dessert! (:) I have no interest in wasting my time with an irrelevant demonstration. Perhaps if you understood the difference, you would see the truth of my arguments and claims. |
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#16
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Setting up a two amp system
"Arny Krueger"
Arny, In the interest of readibility I have snipped all of the foregoing discussion as I hope to summarize it into something a bit more readable. In all fairness I missed a few quotes. It was not intentional. "The bass cabinet contains two 12" woofers and one 8" mid-range. As in the XR19 and later versions of the XRT20, The lower woofer covers the range from 20Hz to 150Hz. The upper woofer goes from 20Hz to 250Hz. The use of two different woofer crossovers reduces interference between the woofers in the upper bass where the distance between them is significant compared to 1/2 wavelength of the sound being radiated." Then he further defines his terminology when discussing equalizers. "...there is the lower bass, upper bass, lower mid-range, upper mid-range and highs.... I arrive at the center frequencies of 30, 150, 500, 1500 and 10,000Hz." Now you can argue what is bass all you want, and you might even make a convincing argument for some, but the fact of the matter is Roger has been doing this professionally for more than 30 years and for a company that has been around for more than 50. I think he knows what he is talking about and if there was a problem with his definitions, others would have corrected him long ago. I have an idea! Why don't you send him an email and explain to him what is bass and how his definitions are wrong. I would love to see what he has to say. I can't wait. I wish it was then now. Getting back to the original statement and to summarize, Scott said "... I want to set up a bi-amped system...using Vandersteen 1 speakers" Bob Morien said "... a woofer amplifier need not have low distortion..." I disagreed saying that distortion in a woofer is audible. To prove my point, I cited where a change in woofer design lowered the measured distortion from 10% to 0.5% which was, and is, clearly audible. The conclusion being that high distortion, either produced or reproduced by a woofer is audible. You disagree. Do I have it right so far? r PS. Arny, for some strange reason I detect some hostility on your part. I do not want to engage in a fight or flame war. Neither is productive or even entertaining. If I said something that made you feel that way, I apologize. It certainly wan not my intent. -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#17
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Setting up a two amp system
"Arny Krueger"
Arny, In the interest of readibility I have snipped all of the foregoing discussion as I hope to summarize it into something a bit more readable. In all fairness I missed a few quotes. It was not intentional. "The bass cabinet contains two 12" woofers and one 8" mid-range. As in the XR19 and later versions of the XRT20, The lower woofer covers the range from 20Hz to 150Hz. The upper woofer goes from 20Hz to 250Hz. The use of two different woofer crossovers reduces interference between the woofers in the upper bass where the distance between them is significant compared to 1/2 wavelength of the sound being radiated." Then he further defines his terminology when discussing equalizers. "...there is the lower bass, upper bass, lower mid-range, upper mid-range and highs.... I arrive at the center frequencies of 30, 150, 500, 1500 and 10,000Hz." Now you can argue what is bass all you want, and you might even make a convincing argument for some, but the fact of the matter is Roger has been doing this professionally for more than 30 years and for a company that has been around for more than 50. I think he knows what he is talking about and if there was a problem with his definitions, others would have corrected him long ago. I have an idea! Why don't you send him an email and explain to him what is bass and how his definitions are wrong. I would love to see what he has to say. I can't wait. I wish it was then now. Getting back to the original statement and to summarize, Scott said "... I want to set up a bi-amped system...using Vandersteen 1 speakers" Bob Morien said "... a woofer amplifier need not have low distortion..." I disagreed saying that distortion in a woofer is audible. To prove my point, I cited where a change in woofer design lowered the measured distortion from 10% to 0.5% which was, and is, clearly audible. The conclusion being that high distortion, either produced or reproduced by a woofer is audible. You disagree. Do I have it right so far? r PS. Arny, for some strange reason I detect some hostility on your part. I do not want to engage in a fight or flame war. Neither is productive or even entertaining. If I said something that made you feel that way, I apologize. It certainly wan not my intent. -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#18
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Setting up a two amp system
"Rich Andrews" wrote in message
.44 "Arny Krueger" In the interest of readability I have snipped all of the foregoing discussion as I hope to summarize it into something a bit more readable. In all fairness I missed a few quotes. It was not intentional. "The bass cabinet contains two 12" woofers and one 8" mid-range. As in the XR19 and later versions of the XRT20, The lower woofer covers the range from 20Hz to 150Hz. The upper woofer goes from 20Hz to 250Hz. The use of two different woofer crossovers reduces interference between the woofers in the upper bass where the distance between them is significant compared to 1/2 wavelength of the sound being radiated." Then he further defines his terminology when discussing equalizers. "...there is the lower bass, upper bass, lower mid-range, upper mid-range and highs.... I arrive at the center frequencies of 30, 150, 500, 1500 and 10,000Hz." IOW his center frequencies are Lower bass - 30 Hz upper bass - 150 Hz Mid-range - 500 Hz Highs - 10,000 Hz These aren't ranges or boundaries, they are and I quote "center frequencies". Now lets estimate Roger's ranges by setting points that are roughly equidistant from adjacent center frequencies, measured in octaves: Lower bass - 30 Hz octaves going up 30 60 120 upper bass - 150 octaves going down 75 150 octaves going up 150 300 600 1200 Mid-range - 500 octaves going down 125 250 500 octaves going up 500 1000 2000 4000 8000 Highs - 10,000 octaves going down 2,500 5,000 10,000 Now, let's figure out some ranges, which is not easy - I may have made some mistakes but... Roger Russell's ranges Lower bass - up to 80 Hz uppper bass - 80 to 275 Hz midrange - 275 to 2250 Hz treble - 2250 to 20,000 Hz Arny Krueger's ranges: Subbass - up to 80 Hz bass - 80 to 200 Hz midrange - 200 to ??? treble ??? to ??? I have some ideas about ??? but I'm not saying what they are at the moment because they are irrelevant to the discussion which is mostly about bass and midrange. Now you can argue what is bass all you want, and you might even make a convincing argument for some, but the fact of the matter is Roger has been doing this professionally for more than 30 years and for a company that has been around for more than 50. I think he knows what he is talking about and if there was a problem with his definitions, others would have corrected him long ago. His definition of bass is 0 to 275 and mine is 0 to 200. I'm not going to argue about 75 Hz - it's less than half an octave at this point. I have an idea! Why don't you send him an email and explain to him what is bass and how his definitions are wrong. I would love to see what he has to say. I can't wait. I wish it was then now. Why bother? We are close enough to agreeing. Getting back to the original statement and to summarize, Scott said "... I want to set up a bi-amped system...using Vandersteen 1 speakers" Bob Morien said "... a woofer amplifier need not have low distortion..." I disagreed saying that distortion in a woofer is audible. To prove my point, I cited where a change in woofer design lowered the measured distortion from 10% to 0.5% which was, and is, clearly audible. The conclusion being that high distortion, either produced or reproduced by a woofer is audible. You disagree. I don't disgree. At the point I disagreed, Morien's post was completely deleted. I didn't respond to Morien's post. Had I responded to Morien's post I would have disagreed because as we can see, woofer amps and bass amps are two different things. Furthermore I addressed my plea for relaxed specifications for bass distortion to the range below 80 Hz. More specifically, I said I was talking about the low end of the frequency range of the subwoofer. Do I have it right so far? No. You confused Roger's center frequencies with extreme frequencies. You keep confusing the woofer range with the bass range, and yet we've got plenty of examples where woofers respond way up into the midrange by either Roger's standard or mine. You read my disagreement, which has been pretty circumspect about saying exactly what I meant, as agreement with Morien's statement, which I disagree with. PS. Arny, for some strange reason I detect some hostility on your part. I do not want to engage in a fight or flame war. Neither is productive or even entertaining. If I said something that made you feel that way, I apologize. It certainly wan not my intent. I'm a bit irritated by all these misunderstandings and misstatements of my position, misstatements of the position of Roger Russell, etc. Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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#19
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Setting up a two amp system
"Rich Andrews" wrote in message
.44 "Arny Krueger" In the interest of readability I have snipped all of the foregoing discussion as I hope to summarize it into something a bit more readable. In all fairness I missed a few quotes. It was not intentional. "The bass cabinet contains two 12" woofers and one 8" mid-range. As in the XR19 and later versions of the XRT20, The lower woofer covers the range from 20Hz to 150Hz. The upper woofer goes from 20Hz to 250Hz. The use of two different woofer crossovers reduces interference between the woofers in the upper bass where the distance between them is significant compared to 1/2 wavelength of the sound being radiated." Then he further defines his terminology when discussing equalizers. "...there is the lower bass, upper bass, lower mid-range, upper mid-range and highs.... I arrive at the center frequencies of 30, 150, 500, 1500 and 10,000Hz." IOW his center frequencies are Lower bass - 30 Hz upper bass - 150 Hz Mid-range - 500 Hz Highs - 10,000 Hz These aren't ranges or boundaries, they are and I quote "center frequencies". Now lets estimate Roger's ranges by setting points that are roughly equidistant from adjacent center frequencies, measured in octaves: Lower bass - 30 Hz octaves going up 30 60 120 upper bass - 150 octaves going down 75 150 octaves going up 150 300 600 1200 Mid-range - 500 octaves going down 125 250 500 octaves going up 500 1000 2000 4000 8000 Highs - 10,000 octaves going down 2,500 5,000 10,000 Now, let's figure out some ranges, which is not easy - I may have made some mistakes but... Roger Russell's ranges Lower bass - up to 80 Hz uppper bass - 80 to 275 Hz midrange - 275 to 2250 Hz treble - 2250 to 20,000 Hz Arny Krueger's ranges: Subbass - up to 80 Hz bass - 80 to 200 Hz midrange - 200 to ??? treble ??? to ??? I have some ideas about ??? but I'm not saying what they are at the moment because they are irrelevant to the discussion which is mostly about bass and midrange. Now you can argue what is bass all you want, and you might even make a convincing argument for some, but the fact of the matter is Roger has been doing this professionally for more than 30 years and for a company that has been around for more than 50. I think he knows what he is talking about and if there was a problem with his definitions, others would have corrected him long ago. His definition of bass is 0 to 275 and mine is 0 to 200. I'm not going to argue about 75 Hz - it's less than half an octave at this point. I have an idea! Why don't you send him an email and explain to him what is bass and how his definitions are wrong. I would love to see what he has to say. I can't wait. I wish it was then now. Why bother? We are close enough to agreeing. Getting back to the original statement and to summarize, Scott said "... I want to set up a bi-amped system...using Vandersteen 1 speakers" Bob Morien said "... a woofer amplifier need not have low distortion..." I disagreed saying that distortion in a woofer is audible. To prove my point, I cited where a change in woofer design lowered the measured distortion from 10% to 0.5% which was, and is, clearly audible. The conclusion being that high distortion, either produced or reproduced by a woofer is audible. You disagree. I don't disgree. At the point I disagreed, Morien's post was completely deleted. I didn't respond to Morien's post. Had I responded to Morien's post I would have disagreed because as we can see, woofer amps and bass amps are two different things. Furthermore I addressed my plea for relaxed specifications for bass distortion to the range below 80 Hz. More specifically, I said I was talking about the low end of the frequency range of the subwoofer. Do I have it right so far? No. You confused Roger's center frequencies with extreme frequencies. You keep confusing the woofer range with the bass range, and yet we've got plenty of examples where woofers respond way up into the midrange by either Roger's standard or mine. You read my disagreement, which has been pretty circumspect about saying exactly what I meant, as agreement with Morien's statement, which I disagree with. PS. Arny, for some strange reason I detect some hostility on your part. I do not want to engage in a fight or flame war. Neither is productive or even entertaining. If I said something that made you feel that way, I apologize. It certainly wan not my intent. I'm a bit irritated by all these misunderstandings and misstatements of my position, misstatements of the position of Roger Russell, etc. Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
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Setting up a two amp system
"Arny Krueger" wrote in message
correction Arny Krueger's ranges: Subbass - up to 120 Hz bass - 120 to 200- Hz midrange - 200 to ??? treble ??? to ??? |
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Setting up a two amp system
"Arny Krueger" wrote in message
correction Arny Krueger's ranges: Subbass - up to 120 Hz bass - 120 to 200- Hz midrange - 200 to ??? treble ??? to ??? |
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Setting up a two amp system
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Setting up a two amp system
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Setting up a two amp system
"Rich Andrews" wrote in message .44... (Scott Dunam) wrote in om: I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. snip Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. Thanks for the information. I was operating under the idea that with each amplifier devoted to a channel there would be a cleaner sound, more power and less noise to each channel. I will look into bridging. Scott Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. r Sounds reasonable to me, but it doesn't seem to contradict my comment; it just doesn't support it. 10% is a very high number, and says little about the audibility of 1% vs. 0.1% distortion. In support of my view, I point out that the relative sensitivity of the ear to bass frequencies is very much less than midrange. For that reason alone, bass distortion should be less audible, because it is closer, and possibly under, the threshold of hearing. My comment is intended for the following interpretation: a user may select an amplifier for subwoofer use with a distortion level of as high as 1%. Perhaps the number should be 0.5%, but the subtle qualitative differences that many people hear should not be audible. The most notable quality of a subwoofer amp is the response near DC, and the large-signal output impedance. The frequently quoted damping factor seems to have little to do with the ability of an amplifier to damp woofer cone motion, because it is measured under small signal conditions. |
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Setting up a two amp system
"Rich Andrews" wrote in message .44... (Scott Dunam) wrote in om: I want to set up a bi-amped system with an Adcom 545 running each channel, and an Adcom GFP-565 pre. Is it possible? If so, how do I hook it up? Using Vandersteen 1 speakers. snip Biamped systems, when identical amps are employed and the crossover within the speaker is used, are, IMHO, a waste of time. In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Another reason for biamplification is to avoid the power loss which occurs in a passive crossover network. To do this, active crossover circuits, inserted before the amplifiers, are used. These circuits are made specifically for the particular speaker. The input of an amplifier receives only low band or high band signals, reducing the total power requirement on the amp, and it is further reduced by absence of crossover dissipation on the output. The amplifier is connected directly to the speaker drivers, or through a simplified network designed to separate only the mid and high frequencies. With the equipment you propose to use, however, biamplification is an empty exercise. If you're looking for a fun experiment, you could try bridging the Adcoms, if they allow this. This results in a multiplication of the instantaneous peak power by a factor of four. While bridging has been questioned as a general practice, some amplifiers seem to respond well to it. I found that it made my Hafler Xl280's come alive. Thanks for the information. I was operating under the idea that with each amplifier devoted to a channel there would be a cleaner sound, more power and less noise to each channel. I will look into bridging. Scott Higher distortion allowable in the bass frequencies is a misconception. http://www.roger-russell.com/xr250.htm "My first listening session with the XR250 brought tears to my eyes. This doesn't usually happen with a new design that's fresh out of the anechoic chamber and reverberant room tests. The human voice with the LD/HP woofers is so clear it made the old woofers sound fuzzy and indistinct." "We then decided to measure IM distortion at a few pairs of frequencies. The old woofer measured 10% and the new LD/HP woofer was 0.5% under the same conditions. This kind of difference should be and is clearly audible." I have heard the LD/HP woofers and the difference *is* plainly audible. r Sounds reasonable to me, but it doesn't seem to contradict my comment; it just doesn't support it. 10% is a very high number, and says little about the audibility of 1% vs. 0.1% distortion. In support of my view, I point out that the relative sensitivity of the ear to bass frequencies is very much less than midrange. For that reason alone, bass distortion should be less audible, because it is closer, and possibly under, the threshold of hearing. My comment is intended for the following interpretation: a user may select an amplifier for subwoofer use with a distortion level of as high as 1%. Perhaps the number should be 0.5%, but the subtle qualitative differences that many people hear should not be audible. The most notable quality of a subwoofer amp is the response near DC, and the large-signal output impedance. The frequently quoted damping factor seems to have little to do with the ability of an amplifier to damp woofer cone motion, because it is measured under small signal conditions. |
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Setting up a two amp system
"Rusty Boudreaux" wrote in message ... "Robert Morein" wrote in message ... In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Although people have done this it doesn't hold up to the claims. High amperage designs are irrelevant. All you need is the appropriate current for a given power demand. If an amplifier can put out X number of watts that's all that is important from an amperage requirement. The woofer/midrange generally needs more power than the tweeter due to the spectral content of music but it's not that big a deal. That doesn't hold with my own experience. A Hafler XL-280 simply doesn't have the bass response of a Parasound HCA-2200ii. On paper, both amps have enough current and enough frequency response to do the job. The difference is real enough to me, but "high amperage" may not be adequately described by the numbers people use. For example, damping factor is measured with small signals. With large signals, some amplifiers don't damp so well. There are great bass amps, and there are so-so bass amps. |
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Setting up a two amp system
"Rusty Boudreaux" wrote in message ... "Robert Morein" wrote in message ... In the past, people have used amplifiers with different properties for bass and treble. For example, a woofer amplifier need not have low distortion, but it should be able to supply high amperage and have a low damping factor. An amplifier for mid and treble is frequently appreciated by the cognoscenti for pleasing tonality or definition. Although people have done this it doesn't hold up to the claims. High amperage designs are irrelevant. All you need is the appropriate current for a given power demand. If an amplifier can put out X number of watts that's all that is important from an amperage requirement. The woofer/midrange generally needs more power than the tweeter due to the spectral content of music but it's not that big a deal. That doesn't hold with my own experience. A Hafler XL-280 simply doesn't have the bass response of a Parasound HCA-2200ii. On paper, both amps have enough current and enough frequency response to do the job. The difference is real enough to me, but "high amperage" may not be adequately described by the numbers people use. For example, damping factor is measured with small signals. With large signals, some amplifiers don't damp so well. There are great bass amps, and there are so-so bass amps. |
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Setting up a two amp system
"Robert Morein" wrote in message
Sounds reasonable to me, but it doesn't seem to contradict my comment; it just doesn't support it. 10% is a very high number, and says little about the audibility of 1% vs. 0.1% distortion. In support of my view, I point out that the relative sensitivity of the ear to bass frequencies is very much less than midrange. For that reason alone, bass distortion should be less audible, because it is closer, and possibly under, the threshold of hearing. Reference: http://www.webervst.com/fm.htm The ear is more sensitive to the frequencies where the harmonics of bass signals fall, than they are to the fundamental frequency. The ear is about 10 dB more sensitive to a 300 Hz sixth harmonic of a 50 Hz 85 dB tone than the fundamental, for example. The threshold of hearing at 50 Hz is about 50 dB, so it's possible to hear a 60 dB fundamental, but ear is about 30 dB more sensitive to its 300 Hz harmonic. OTOH, at 100 dB the ear's sensitivity is relatively flat from 20 Hz to 1 KHz. My comment is intended for the following interpretation: a user may select an amplifier for subwoofer use with a distortion level of as high as 1%. In the 21st century there is no practical way to come up with a modern even vaguely credible power amp with 1% THD below clipping. Those flat plate subwoofer amps sold mail order for $50 and up have 0.1% or less THD below clipping. If you want a power amp with more distortion than that, look at SETs or tubed guitar amps, or amps with built-in nonlinear distortion generators. Perhaps the number should be 0.5%, but the subtle qualitative differences that many people hear should not be audible. The most notable quality of a subwoofer amp is the response near DC, Program material from clean sources lacks content at frequencies near DC. There are usually so many coupling caps in the production chain that real-world response of recordings falls off very rapidly below 10-20 Hz. Microphones with flat response that's flat below 50 Hz, let alone 10 Hz are very rare. and the large-signal output impedance. Another area where there are few relevant differences among modern power amps of even modest quality levels. Furthermore, outside of clipping, there are few significant differences between small-signal and large-signal output impedance for modern amps. The frequently quoted damping factor seems to have little to do with the ability of an amplifier to damp woofer cone motion, because it is measured under small signal conditions. Damping factor has the broadest and easiest-to-understand relevance when treated as what it really is - another way of talking about amplifier output impedance. Long term readers of the rec.audio.* newsgroups should be aware of the fact that a number of well-experienced and highly-qualified writers have spoken against the use of the term, over the years. I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. Empirical evidence does have relevance! A good archive of this kind of data can be found at Stereophile's web site. |
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Setting up a two amp system
"Robert Morein" wrote in message
Sounds reasonable to me, but it doesn't seem to contradict my comment; it just doesn't support it. 10% is a very high number, and says little about the audibility of 1% vs. 0.1% distortion. In support of my view, I point out that the relative sensitivity of the ear to bass frequencies is very much less than midrange. For that reason alone, bass distortion should be less audible, because it is closer, and possibly under, the threshold of hearing. Reference: http://www.webervst.com/fm.htm The ear is more sensitive to the frequencies where the harmonics of bass signals fall, than they are to the fundamental frequency. The ear is about 10 dB more sensitive to a 300 Hz sixth harmonic of a 50 Hz 85 dB tone than the fundamental, for example. The threshold of hearing at 50 Hz is about 50 dB, so it's possible to hear a 60 dB fundamental, but ear is about 30 dB more sensitive to its 300 Hz harmonic. OTOH, at 100 dB the ear's sensitivity is relatively flat from 20 Hz to 1 KHz. My comment is intended for the following interpretation: a user may select an amplifier for subwoofer use with a distortion level of as high as 1%. In the 21st century there is no practical way to come up with a modern even vaguely credible power amp with 1% THD below clipping. Those flat plate subwoofer amps sold mail order for $50 and up have 0.1% or less THD below clipping. If you want a power amp with more distortion than that, look at SETs or tubed guitar amps, or amps with built-in nonlinear distortion generators. Perhaps the number should be 0.5%, but the subtle qualitative differences that many people hear should not be audible. The most notable quality of a subwoofer amp is the response near DC, Program material from clean sources lacks content at frequencies near DC. There are usually so many coupling caps in the production chain that real-world response of recordings falls off very rapidly below 10-20 Hz. Microphones with flat response that's flat below 50 Hz, let alone 10 Hz are very rare. and the large-signal output impedance. Another area where there are few relevant differences among modern power amps of even modest quality levels. Furthermore, outside of clipping, there are few significant differences between small-signal and large-signal output impedance for modern amps. The frequently quoted damping factor seems to have little to do with the ability of an amplifier to damp woofer cone motion, because it is measured under small signal conditions. Damping factor has the broadest and easiest-to-understand relevance when treated as what it really is - another way of talking about amplifier output impedance. Long term readers of the rec.audio.* newsgroups should be aware of the fact that a number of well-experienced and highly-qualified writers have spoken against the use of the term, over the years. I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. Empirical evidence does have relevance! A good archive of this kind of data can be found at Stereophile's web site. |
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Bad Scientist Alert!
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. |
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Bad Scientist Alert!
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. |
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Bad Scientist Alert!
"Robert Morein" wrote in message
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Mea Culpa. |
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Bad Scientist Alert!
"Robert Morein" wrote in message
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Mea Culpa. |
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Bad Scientist Alert!
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message "Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Mea Culpa. It really doesn't matter what you claim your methodology is. You taint it with your touch. |
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Bad Scientist Alert!
"Arny Krueger" wrote in message ... "Robert Morein" wrote in message "Arny Krueger" wrote in message ... "Robert Morein" wrote in message [snip] I'd like to see argument with these assertions restricted to people who have actually measured these parameters for modern power amps in the past 10 years. [snip] I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Mea Culpa. It really doesn't matter what you claim your methodology is. You taint it with your touch. |
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Bad Scientist Alert!
Brian L. McCarty (pretending to be "Robert Morein") wrote...
I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. "Arny Krueger" wrote ... Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Arny, PLEASE DON'T FEED THE TROLLS! Especially this one! |
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Bad Scientist Alert!
Brian L. McCarty (pretending to be "Robert Morein") wrote...
I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. "Arny Krueger" wrote ... Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Arny, PLEASE DON'T FEED THE TROLLS! Especially this one! |
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Setting up a two amp system
"Robert Morein" wrote in message
... That doesn't hold with my own experience. A Hafler XL-280 simply doesn't have the bass response of a Parasound HCA-2200ii. On paper, both amps have enough current and enough frequency response to do the job. Something else must be at play. Dynamic headroom, clipping behavior, etc. For example, damping factor is measured with small signals. With large signals, some amplifiers don't damp so well. As I said, damping factor is useless. DF is actually a measure of how poorly an amp can damp the system. In all but the most pathologically deficient amps the vast majority of damping is done by the voice coil resistance, suspension, and air inside the enclosure. Even a very low DF is unable to damp the system at resonance. Dick Pierce penned a very nice paper on the subject which can be found in the google archive. You may have to copy both pieces of the link into your browser due to word wrap. DAMPING FACTOR: EFFECTS ON SYSTEM RESPONSE A TECHNICAL ANALYSIS Dick Pierce Professional Audio Development http://groups.google.com/groups?q=g:...dq=&hl=en&lr=& ie=UTF-8&selm=GE1tJy.BIp%40world.std.com&rnum=1 or you can do an Advanced Group Search and search for message ID = There are great bass amps, and there are so-so bass amps. Agreed, but damping factor is no indication. |
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Setting up a two amp system
"Robert Morein" wrote in message
... That doesn't hold with my own experience. A Hafler XL-280 simply doesn't have the bass response of a Parasound HCA-2200ii. On paper, both amps have enough current and enough frequency response to do the job. Something else must be at play. Dynamic headroom, clipping behavior, etc. For example, damping factor is measured with small signals. With large signals, some amplifiers don't damp so well. As I said, damping factor is useless. DF is actually a measure of how poorly an amp can damp the system. In all but the most pathologically deficient amps the vast majority of damping is done by the voice coil resistance, suspension, and air inside the enclosure. Even a very low DF is unable to damp the system at resonance. Dick Pierce penned a very nice paper on the subject which can be found in the google archive. You may have to copy both pieces of the link into your browser due to word wrap. DAMPING FACTOR: EFFECTS ON SYSTEM RESPONSE A TECHNICAL ANALYSIS Dick Pierce Professional Audio Development http://groups.google.com/groups?q=g:...dq=&hl=en&lr=& ie=UTF-8&selm=GE1tJy.BIp%40world.std.com&rnum=1 or you can do an Advanced Group Search and search for message ID = There are great bass amps, and there are so-so bass amps. Agreed, but damping factor is no indication. |
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Bad Scientist Alert!
"Richard Crowley" wrote in message ... Brian L. McCarty (pretending to be "Robert Morein") wrote... I'd like to see you recognized for what you a a charlatan, a fraud, and a bad scientist. "Arny Krueger" wrote ... Yup, looking for people who can back their theories up with emperical evidence clearly brands me with the stigma being a bad scientist. Arny, PLEASE DON'T FEED THE TROLLS! Especially this one! Apparently, there is some question as to whether my post was genuine. I have a big beef with Arny Krueger, and I have labeled him a bad scientist, and I believe I am not without justification. The "ABX" protocol is useful, and fundamental to precise scientific investigation in many areas of human perception. Therefore, my extreme deprecation of Arny Krueger is not because he espouses ABX per se. However, as has been the case throughout the history of science, bad science has coexisted with good science, and in very large proportion. Most currently accepted scientific facts were preceded by theories that had the standing of fact and that were later proved false. Arny Krueger is, in my opinion, part of that large proportion of would be scientists who have misused the label of science. Why people do this is a matter of conjecture. All good scientists have an open mind and a dispassionate attitude toward their subject material. It should be apparent that Arny is quite certain, with no room for error, on all the subjects on which he espouses, and that he is extremely passionate. This is a recipe for contamination; it prepares for assassination of the truth. On the other side of this room are a large number of audiophiles. Many, like myself, take no pride in their hearing, yet find simple phenomena that constantly reoccur. One of these is that some combinations of amplifiers and speakers sound different from other amplifiers with the same speakers. The claim is not made that one can tell the difference between all, or even most, amplifiers. Nor is it claimed that expensive amplifiers sound different from cheap ones. However, I personally possess quite a number of amplifiers with seemingly distinct sound signatures. All of these amplifiers are, apparently, "good", in that they are of reputable make, heavily built, and definitely not defective, since in my case, I have more than one of just about every amp I own. For this reason, I advocate to the audiophile that he try different amplifiers with his speakers, in whatever experiment conditions will allow. If he has ABX handy, by all means use it, but then, this discussion is a bit elementary for him. If he has a method of precision matching levels, use it, by all means. However, when faced with virtually no resources, if the only person the audiophile has to satisfy is himself, he should do it by switching the wires himself. He may find a difference; he may not; no harm done. If he finds an amplifier that pleases him more, he should choose that amplifier. He should not believe he heard nothing, or be discouraged from doing this, because Arny Krueger says it's a useless exercise. Arny's uncopromising position seems to be that "all properly operating amplifiers of a certain power class, when level matched, are indistinguishable." I would certainly agree with this if "properly operating" meant "perfect", but it does not, because there are no perfect amplifiers. Arny has strung together a lot of methodology with the assumption that the logic is transitive. In other words, if A implies B, and B implies C, then A implies C. In this way, he purports to "prove", via samples on his ABX website, that the ear is far too tolerant of distortion to hear the difference between "properly operating amplifiers." To me, and to many other audiophiles, this is analogous to ****ing on our backs and calling it rain. People have proved the existence of God, and disproved the existence of God. Have they proved anything? No. A good scientist, when confronted by a very large body of people who apparently believe that some good amplifiers sound better than other good amplifiers, when coupled to some good speakers, would open up his imagination, his spirit, his curiosity, and his will, to find out what's going on. Arny claims to be protecting the consumer from himself. It is unquestionably the case that many audiophiles DO delude themselves into believing that they hear things that they don't. This usually happens as the hobby gets a little old, and they seek to repeat the thrill of discovering new things. But the hobby has many curmudgeons like myself, who own old, discarded things. I have no stake in preferring any one of my Parasounds to my Haflers to my Acoustats. I chose these amplifiers a long time ago, after passing over others. They are not new, and they do not thrill me, and when I'm done switching around, I have just as many as I started with. Arny may claim that I am still contaminated with my own humanity, but it is hard to find my motive. I am reminded of the mistake NASA made with the Hubble Space Telescope. Each optic was rigorously checked, but they didn't have the money to put the thing through a test on the ground. Good minds made a terrible mistake. Ironically, Arny Krueger is a fairly knowledgeable guy. Unfortunately, his knowledge is not accompanied by wisdom, nor an understanding of the limits of his knowledge. Usenet provides an outlet for people who want to pontificate. Many of us have a feeling of pride when we answer a question that may be read by several thousand people. But we must remember that humility is just a word, it is a principle of action. In this case, to be humble as a scientist means to openly accept and investigate, and encourage the possibility that any theory one has authored is wrong. |
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