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#41
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Old speaker boxes
Foam surrounds and ports will never give accurate response.
It only allows for a slower base [sic!!!] response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass-reflex speakers count on a rigid surround and tuned port to accomplish the same task. Pardon my bluntness, but you don't know what the h*** you're talking about. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. "Good" and "bass reflex" is a contradiction in terms. |
#42
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Old speaker boxes
Foam surrounds and ports will never give accurate response.
It only allows for a slower base [sic!!!] response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass-reflex speakers count on a rigid surround and tuned port to accomplish the same task. Pardon my bluntness, but you don't know what the h*** you're talking about. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. "Good" and "bass reflex" is a contradiction in terms. |
#43
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Old speaker boxes
Fine, tell my teachers that they didn't know what they were talking about.
I must admit that rolled suspension speakers have probably improved since I started dealing with sound, but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds This is not to start a flame, but if I'm missing something??? Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. John Mikey wrote: You should consult a speaker building book. "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#44
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Old speaker boxes
Fine, tell my teachers that they didn't know what they were talking about.
I must admit that rolled suspension speakers have probably improved since I started dealing with sound, but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds This is not to start a flame, but if I'm missing something??? Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. John Mikey wrote: You should consult a speaker building book. "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#45
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Old speaker boxes
Fine, tell my teachers that they didn't know what they were talking about.
I must admit that rolled suspension speakers have probably improved since I started dealing with sound, but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds This is not to start a flame, but if I'm missing something??? Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. John Mikey wrote: You should consult a speaker building book. "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#46
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Old speaker boxes
Fine, tell my teachers that they didn't know what they were talking about.
I must admit that rolled suspension speakers have probably improved since I started dealing with sound, but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds This is not to start a flame, but if I'm missing something??? Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. John Mikey wrote: You should consult a speaker building book. "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#47
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Old speaker boxes
"William Sommerwerck" wrote in message ... Pardon my bluntness, but you don't know what the h*** you're talking about. Are you looking in a morror by any chance? To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. TonyP. |
#48
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Old speaker boxes
"William Sommerwerck" wrote in message ... Pardon my bluntness, but you don't know what the h*** you're talking about. Are you looking in a morror by any chance? To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. TonyP. |
#49
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Old speaker boxes
"William Sommerwerck" wrote in message ... Pardon my bluntness, but you don't know what the h*** you're talking about. Are you looking in a morror by any chance? To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. TonyP. |
#50
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Old speaker boxes
"William Sommerwerck" wrote in message ... Pardon my bluntness, but you don't know what the h*** you're talking about. Are you looking in a morror by any chance? To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. TonyP. |
#51
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Old speaker boxes
Pardon my bluntness, but you don't know what the h***
you're talking about. Are you looking in a morror [sic] by any chance? I'm a degreed EE, and I reviewed audio equipment for over a decade. You're trying to apply "common sense" to an issue where math and physics provide a more-accurate explanation of what's going on. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. READ WHAT I WROTE. "More quickly" means more quickly than a bass-reflex enclosure. Do I have to spell out everything in total, utter, mindless detail? To the best of my knowledge, a driver cannot "return to rest" before the signal. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. Sorry, but science _is_ on my side. A sealed box is superior to ported. Why? Because (given a maximally flat design) a sealed box rolls off at 12db/8ve, while a ported box falls at 24dB/8ve. The tradeoff is that the ported box gains efficiency in exchange for the more-abrupt rolloff. Which appears to be the reason that most companies have switched to ported designs -- even AR. All other things being equal (including the corner frequency), would you rather listen to a speaker with a two-pole rolloff, or a four-pole rolloff? Well, which has less phase shift? Lower group delay? Rings less? It's also possible to build a sealed-box system that is so overdamped that it rolls off at 6b/8ve. Such a design lends itself to a compensating bass boost from the amplifier. To the best of my knowledge, only KLH ever produced such a system, and that was 40+ years ago. The box woofers for the Apogee systems used a second-order slow-rolloff alignment. (It was not Chebyschev. I forget which it was.) In "High-Performance Loudspeakers" (a book which, oddly, pays almost no attention to electrostatic and orthodynamic/ribbon systems) the author claims that listeners prefer overdamped bass, even when the corner frequency is higher than that of a sealed or ported box. This isn't at all surprising, because an overdamped design, thought it "lingers," does not ring, and it has _more_ output below the corner frequency than a sealed or ported design. |
#52
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Old speaker boxes
Pardon my bluntness, but you don't know what the h***
you're talking about. Are you looking in a morror [sic] by any chance? I'm a degreed EE, and I reviewed audio equipment for over a decade. You're trying to apply "common sense" to an issue where math and physics provide a more-accurate explanation of what's going on. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. READ WHAT I WROTE. "More quickly" means more quickly than a bass-reflex enclosure. Do I have to spell out everything in total, utter, mindless detail? To the best of my knowledge, a driver cannot "return to rest" before the signal. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. Sorry, but science _is_ on my side. A sealed box is superior to ported. Why? Because (given a maximally flat design) a sealed box rolls off at 12db/8ve, while a ported box falls at 24dB/8ve. The tradeoff is that the ported box gains efficiency in exchange for the more-abrupt rolloff. Which appears to be the reason that most companies have switched to ported designs -- even AR. All other things being equal (including the corner frequency), would you rather listen to a speaker with a two-pole rolloff, or a four-pole rolloff? Well, which has less phase shift? Lower group delay? Rings less? It's also possible to build a sealed-box system that is so overdamped that it rolls off at 6b/8ve. Such a design lends itself to a compensating bass boost from the amplifier. To the best of my knowledge, only KLH ever produced such a system, and that was 40+ years ago. The box woofers for the Apogee systems used a second-order slow-rolloff alignment. (It was not Chebyschev. I forget which it was.) In "High-Performance Loudspeakers" (a book which, oddly, pays almost no attention to electrostatic and orthodynamic/ribbon systems) the author claims that listeners prefer overdamped bass, even when the corner frequency is higher than that of a sealed or ported box. This isn't at all surprising, because an overdamped design, thought it "lingers," does not ring, and it has _more_ output below the corner frequency than a sealed or ported design. |
#53
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Old speaker boxes
Pardon my bluntness, but you don't know what the h***
you're talking about. Are you looking in a morror [sic] by any chance? I'm a degreed EE, and I reviewed audio equipment for over a decade. You're trying to apply "common sense" to an issue where math and physics provide a more-accurate explanation of what's going on. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. READ WHAT I WROTE. "More quickly" means more quickly than a bass-reflex enclosure. Do I have to spell out everything in total, utter, mindless detail? To the best of my knowledge, a driver cannot "return to rest" before the signal. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. Sorry, but science _is_ on my side. A sealed box is superior to ported. Why? Because (given a maximally flat design) a sealed box rolls off at 12db/8ve, while a ported box falls at 24dB/8ve. The tradeoff is that the ported box gains efficiency in exchange for the more-abrupt rolloff. Which appears to be the reason that most companies have switched to ported designs -- even AR. All other things being equal (including the corner frequency), would you rather listen to a speaker with a two-pole rolloff, or a four-pole rolloff? Well, which has less phase shift? Lower group delay? Rings less? It's also possible to build a sealed-box system that is so overdamped that it rolls off at 6b/8ve. Such a design lends itself to a compensating bass boost from the amplifier. To the best of my knowledge, only KLH ever produced such a system, and that was 40+ years ago. The box woofers for the Apogee systems used a second-order slow-rolloff alignment. (It was not Chebyschev. I forget which it was.) In "High-Performance Loudspeakers" (a book which, oddly, pays almost no attention to electrostatic and orthodynamic/ribbon systems) the author claims that listeners prefer overdamped bass, even when the corner frequency is higher than that of a sealed or ported box. This isn't at all surprising, because an overdamped design, thought it "lingers," does not ring, and it has _more_ output below the corner frequency than a sealed or ported design. |
#54
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Old speaker boxes
Pardon my bluntness, but you don't know what the h***
you're talking about. Are you looking in a morror [sic] by any chance? I'm a degreed EE, and I reviewed audio equipment for over a decade. You're trying to apply "common sense" to an issue where math and physics provide a more-accurate explanation of what's going on. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. If the speaker returns to zero more quickly than the input signal, the box is definitely overdamped. READ WHAT I WROTE. "More quickly" means more quickly than a bass-reflex enclosure. Do I have to spell out everything in total, utter, mindless detail? To the best of my knowledge, a driver cannot "return to rest" before the signal. "Good" and "bass reflex" is a contradiction in terms. You might argue that good (sound?) and moving coil loudspeakers are a contradiction in terms (I wouldn't) but science is not on your side if you are simply stating that sealed boxes are necessarily better than ported. Sorry, but science _is_ on my side. A sealed box is superior to ported. Why? Because (given a maximally flat design) a sealed box rolls off at 12db/8ve, while a ported box falls at 24dB/8ve. The tradeoff is that the ported box gains efficiency in exchange for the more-abrupt rolloff. Which appears to be the reason that most companies have switched to ported designs -- even AR. All other things being equal (including the corner frequency), would you rather listen to a speaker with a two-pole rolloff, or a four-pole rolloff? Well, which has less phase shift? Lower group delay? Rings less? It's also possible to build a sealed-box system that is so overdamped that it rolls off at 6b/8ve. Such a design lends itself to a compensating bass boost from the amplifier. To the best of my knowledge, only KLH ever produced such a system, and that was 40+ years ago. The box woofers for the Apogee systems used a second-order slow-rolloff alignment. (It was not Chebyschev. I forget which it was.) In "High-Performance Loudspeakers" (a book which, oddly, pays almost no attention to electrostatic and orthodynamic/ribbon systems) the author claims that listeners prefer overdamped bass, even when the corner frequency is higher than that of a sealed or ported box. This isn't at all surprising, because an overdamped design, thought it "lingers," does not ring, and it has _more_ output below the corner frequency than a sealed or ported design. |
#55
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Old speaker boxes
Sanders wrote in message ...
Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#56
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Old speaker boxes
Sanders wrote in message ...
Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#57
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Old speaker boxes
Sanders wrote in message ...
Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#58
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Old speaker boxes
Sanders wrote in message ...
Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#59
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Old speaker boxes
I bow out from the group as my knowledge learned is useless.
Good luck all !!! John Dick Pierce wrote: Sanders wrote in message ... Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#60
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Old speaker boxes
I bow out from the group as my knowledge learned is useless.
Good luck all !!! John Dick Pierce wrote: Sanders wrote in message ... Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#61
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Old speaker boxes
I bow out from the group as my knowledge learned is useless.
Good luck all !!! John Dick Pierce wrote: Sanders wrote in message ... Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#62
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Old speaker boxes
I bow out from the group as my knowledge learned is useless.
Good luck all !!! John Dick Pierce wrote: Sanders wrote in message ... Fine, tell my teachers that they didn't know what they were talking about. First, since you failed to tell us who your teacher were, that's kind of difficult, isn't it. Second, we do not know if what you are telling us is their misinterpretations of the physics of loudspeakers, or yours. You're the one that made the statements, thus we criticize those words. If you would be so kind as to supply their course notes and texts, I would be more than happy to tell them they are wrong, but for time being, the best I can do is tell you that you are wrong. Third, since you're into "well tell THEM they're wrong," I suggest you get yourself a copy of the following articles: Thiele, A. N., "Loudspeakers in Vented Boxes," Part I, JAES 1971 May, Part II, 1971 June (Reprint from Proc. IRE Aus 1961 Aug) Small, R. H., "Direct-Radiator Loudspeaker System Analysis," JAES, 1972 June Small, R. H., "Closed-Box Loudspeaker Systems," "Part I - Analysis" JAES, 1972 Dec, "Part II - Synthesis," JAES 173 Jan-Feb Small, R. H., "Vented-Box Loudspeaker Systems," Part I - Small-Signal Analysis" JAES, 1973 June, "Part II - Large Signal Analysis," JAES 1973 Jul/Aug, "Part III - Synthesis," JAES 1973 Sep, "Part IV - Appendices," JAES 1973 Oct. Now, Show us, with the same level of mathematical rigor that they employed in their work that they are wrong, and you have a shot at the title. Note the two authors, two of many, that I cited, Messrs. Thiele and Small, and perhaps you might ask yourself why THE dominant model and design basis for all direct-radiator system designed is designated the "Thiele-Small" model. Once you have knocked them off, then I'll be happy to supply further citations. I must admit that rolled suspension speakers have probably improved since I started dealing with sound, "Rolled suspension" drivers were invented in the late 1950's and became commonplace in the early 1960's. Are you suggesting that your last involvement in sound was 40 years ago, and that you have missed the entire development since then. That might explain the fact that you seem to be unaware of the work of Messr's Thiele, Small, Benson and others. but back when I started, what I said was the truth for all things the company I worked for went with, and they are still in business so they must of known something about what the hell they were doing. Again, since you fail to mention WHO this company is, your reference to them has zero credibility. And, it should be noted, there are a number of companies that suffer from longevity undeserved given their "expertise." Note, for example, General Motors, about to introduce a hyprid gas-electric SUV that gets a whopping 15 miles per gallon. What idiot dreamt THAT up? The rolled speakers spiders were not very rigid in the begining of their use compared to the rigid surrounds And precisely what does this mean? This is not to start a flame, but if I'm missing something??? Yes, you're missing the entire physical foundational background to direct radiator loudspeaker system behavior. Note the citations above as a starting point to correct said deficiency. Tuned ports worked best with rigid speakers, which now seem to be rare in use anymore because larger amps allow for more inefficent speakers than when I started. Sorry, my friend, but this is yet more nonsense. You're making assertions with absolutely no physical foundation to support them. The efficiency of a driver is NOT dependent upon the suspension stiffness, as shown by Thiele, Small and even going as far back as MacClachlin (1938). The efficiency, expressed in terms of fundamental electro-mechanical parameters, is: p0 B^2 l^2 n = ------ * ---------- 2 pi c Re Mms^2 where p0 is the density of air (~ 1.18 kg/m^3) c is the velocity of sound (~ 342 m/s), B is the flux density in the gap (in Tesla), l is the length of the voice coil conductor in the gap (meters), Re is the DC resistance of the voice coil, and Mms is the effective moving mass of the driver. Please note the complete absence of a stiffness or a compliance term in this realtion. Should you feel this equation is in error, it is equation 11 in the second citation above, and I might suggest you take it up with Mr. Small, the author. All I did was comment on all the different things we tried with speakers and which did the best RTA tests we did with them. Well, you in fact, made specific testable technical assertions, which when tested were shown to be wrong. And some of what you asserted was self-contradictory. Further, you alluded to transient behavior of speakers. RTA, by which I assume you mean "real-time analyzers," are generally represented by parallel-narrow-band bandpass filter analyzers. Such devices are utterly incapable of evaluating the transient response of systems. Now, when I talk about "transient response," I'm speaking from the viewpoint of using impulse or MLS stimulus driven FFT systems which, by their very nature measure transient response. As I have several different versions here, along with the sufficently wide bandwidth ancillary equipment to support them, I would humbly venture to suggest that the several thousands of measurements I have conducted over the last quarter century or so fail completely to provde ANY data that supports your assertions. I would point you, again, to the above citations and, should you need them, I'd be happy to provide several dozen more that also not only fail to support your assertions, but contradict them rather unambiguously. So, in the meantime, who ARE these teachers that mislead you? Perhaps you could apply for at least a partial tuition refund. What is this company that seemingly has not studied the rather vast technical literature base on direct-radiator loudspeaker physics? Perhaps they could use some consulting? :-) |
#63
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Old speaker boxes
Sanders topposted:
Foam surrounds and ports will never .... Dick already commented. I can't seem to locate the beginning of this, but a long tail of old stuff was appended and there never did seen to be a proper follow up to the original question because the box working principle may be different from the simple bass reflex that is assumed by the guy that did follow up. Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). It would have been very helpful if simple, plain facts, such as manufacturer and model of speaker had been included. Usually when a layer of fabric was added to a bass reflex port it was as an intentional flow resistance. Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Hmm ... Is it safe to remove this or should i replace the cloth? There is not sufficient information for a reply to be given. The simplest solution is to close the port, it will cost a bit of fullness in the bass but probably allow deeper bass and more precise bass. Try it, you may or may not like it, it is the "safe bet" solution on your skill level and with the information provided. There is the equally simple solution of removing t he remainder of the cloth, it may have been intended to be a flow resistance, but it obviously doesn't work like that anymore anyway. So removing it doesn't change the current situation, and it probably remedies some of the problems. or should i just replace it with another part? Assuming that I understood this right and that this is about a bass reflex port with a flow resistance, yes, replacing with similar cloth is an excellent idea. The original selection of cloth and/or number of layers of cloth was made by listening, and listening is the way to do it. Compare with the sound with the port closed and with the port without the flow resistance, and aim for a compromise a bit nearer to "closed" than to "open". would adding more of these holes produce better sound? As asked: NO! It may be that the choice of using a flow resistance was made instead of the choice of adding a length of tube to the port or instead of using a longer tube. This then enters the "advanced, not for beginners" stuff. Make an extensible tube, from two tubes that can slide inside one another, reasonably tight, and fitting the hole that is already in the box or make several tubes of differing lenghts, say 3,5,7,9 inches, and listen. If the tube is too short, then the bass gets sloppy, the longer it is the deeper it goes, but at the price of fullness. With some length it will be "just right" and you could end up having a real improvement of the cabinet. It may also be that you end up preferring the tightness of having the cabinet closed instead of ported. The room is a part of this too, and you supply zero real information, so this is about as much reply as can possibly be given, and then some. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... The above kinda agrees with this. If it is indeed an "acoustic vent" design then adding a lenght of tube to the port instead may be "good for it". Kinda agrees only, I don't want to get into the technical detail, it is not really relevant in the context anyway. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#64
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Old speaker boxes
Sanders topposted:
Foam surrounds and ports will never .... Dick already commented. I can't seem to locate the beginning of this, but a long tail of old stuff was appended and there never did seen to be a proper follow up to the original question because the box working principle may be different from the simple bass reflex that is assumed by the guy that did follow up. Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). It would have been very helpful if simple, plain facts, such as manufacturer and model of speaker had been included. Usually when a layer of fabric was added to a bass reflex port it was as an intentional flow resistance. Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Hmm ... Is it safe to remove this or should i replace the cloth? There is not sufficient information for a reply to be given. The simplest solution is to close the port, it will cost a bit of fullness in the bass but probably allow deeper bass and more precise bass. Try it, you may or may not like it, it is the "safe bet" solution on your skill level and with the information provided. There is the equally simple solution of removing t he remainder of the cloth, it may have been intended to be a flow resistance, but it obviously doesn't work like that anymore anyway. So removing it doesn't change the current situation, and it probably remedies some of the problems. or should i just replace it with another part? Assuming that I understood this right and that this is about a bass reflex port with a flow resistance, yes, replacing with similar cloth is an excellent idea. The original selection of cloth and/or number of layers of cloth was made by listening, and listening is the way to do it. Compare with the sound with the port closed and with the port without the flow resistance, and aim for a compromise a bit nearer to "closed" than to "open". would adding more of these holes produce better sound? As asked: NO! It may be that the choice of using a flow resistance was made instead of the choice of adding a length of tube to the port or instead of using a longer tube. This then enters the "advanced, not for beginners" stuff. Make an extensible tube, from two tubes that can slide inside one another, reasonably tight, and fitting the hole that is already in the box or make several tubes of differing lenghts, say 3,5,7,9 inches, and listen. If the tube is too short, then the bass gets sloppy, the longer it is the deeper it goes, but at the price of fullness. With some length it will be "just right" and you could end up having a real improvement of the cabinet. It may also be that you end up preferring the tightness of having the cabinet closed instead of ported. The room is a part of this too, and you supply zero real information, so this is about as much reply as can possibly be given, and then some. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... The above kinda agrees with this. If it is indeed an "acoustic vent" design then adding a lenght of tube to the port instead may be "good for it". Kinda agrees only, I don't want to get into the technical detail, it is not really relevant in the context anyway. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#65
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Old speaker boxes
Sanders topposted:
Foam surrounds and ports will never .... Dick already commented. I can't seem to locate the beginning of this, but a long tail of old stuff was appended and there never did seen to be a proper follow up to the original question because the box working principle may be different from the simple bass reflex that is assumed by the guy that did follow up. Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). It would have been very helpful if simple, plain facts, such as manufacturer and model of speaker had been included. Usually when a layer of fabric was added to a bass reflex port it was as an intentional flow resistance. Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Hmm ... Is it safe to remove this or should i replace the cloth? There is not sufficient information for a reply to be given. The simplest solution is to close the port, it will cost a bit of fullness in the bass but probably allow deeper bass and more precise bass. Try it, you may or may not like it, it is the "safe bet" solution on your skill level and with the information provided. There is the equally simple solution of removing t he remainder of the cloth, it may have been intended to be a flow resistance, but it obviously doesn't work like that anymore anyway. So removing it doesn't change the current situation, and it probably remedies some of the problems. or should i just replace it with another part? Assuming that I understood this right and that this is about a bass reflex port with a flow resistance, yes, replacing with similar cloth is an excellent idea. The original selection of cloth and/or number of layers of cloth was made by listening, and listening is the way to do it. Compare with the sound with the port closed and with the port without the flow resistance, and aim for a compromise a bit nearer to "closed" than to "open". would adding more of these holes produce better sound? As asked: NO! It may be that the choice of using a flow resistance was made instead of the choice of adding a length of tube to the port or instead of using a longer tube. This then enters the "advanced, not for beginners" stuff. Make an extensible tube, from two tubes that can slide inside one another, reasonably tight, and fitting the hole that is already in the box or make several tubes of differing lenghts, say 3,5,7,9 inches, and listen. If the tube is too short, then the bass gets sloppy, the longer it is the deeper it goes, but at the price of fullness. With some length it will be "just right" and you could end up having a real improvement of the cabinet. It may also be that you end up preferring the tightness of having the cabinet closed instead of ported. The room is a part of this too, and you supply zero real information, so this is about as much reply as can possibly be given, and then some. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... The above kinda agrees with this. If it is indeed an "acoustic vent" design then adding a lenght of tube to the port instead may be "good for it". Kinda agrees only, I don't want to get into the technical detail, it is not really relevant in the context anyway. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#66
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Old speaker boxes
Sanders topposted:
Foam surrounds and ports will never .... Dick already commented. I can't seem to locate the beginning of this, but a long tail of old stuff was appended and there never did seen to be a proper follow up to the original question because the box working principle may be different from the simple bass reflex that is assumed by the guy that did follow up. Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). It would have been very helpful if simple, plain facts, such as manufacturer and model of speaker had been included. Usually when a layer of fabric was added to a bass reflex port it was as an intentional flow resistance. Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Hmm ... Is it safe to remove this or should i replace the cloth? There is not sufficient information for a reply to be given. The simplest solution is to close the port, it will cost a bit of fullness in the bass but probably allow deeper bass and more precise bass. Try it, you may or may not like it, it is the "safe bet" solution on your skill level and with the information provided. There is the equally simple solution of removing t he remainder of the cloth, it may have been intended to be a flow resistance, but it obviously doesn't work like that anymore anyway. So removing it doesn't change the current situation, and it probably remedies some of the problems. or should i just replace it with another part? Assuming that I understood this right and that this is about a bass reflex port with a flow resistance, yes, replacing with similar cloth is an excellent idea. The original selection of cloth and/or number of layers of cloth was made by listening, and listening is the way to do it. Compare with the sound with the port closed and with the port without the flow resistance, and aim for a compromise a bit nearer to "closed" than to "open". would adding more of these holes produce better sound? As asked: NO! It may be that the choice of using a flow resistance was made instead of the choice of adding a length of tube to the port or instead of using a longer tube. This then enters the "advanced, not for beginners" stuff. Make an extensible tube, from two tubes that can slide inside one another, reasonably tight, and fitting the hole that is already in the box or make several tubes of differing lenghts, say 3,5,7,9 inches, and listen. If the tube is too short, then the bass gets sloppy, the longer it is the deeper it goes, but at the price of fullness. With some length it will be "just right" and you could end up having a real improvement of the cabinet. It may also be that you end up preferring the tightness of having the cabinet closed instead of ported. The room is a part of this too, and you supply zero real information, so this is about as much reply as can possibly be given, and then some. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... The above kinda agrees with this. If it is indeed an "acoustic vent" design then adding a lenght of tube to the port instead may be "good for it". Kinda agrees only, I don't want to get into the technical detail, it is not really relevant in the context anyway. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#67
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Old speaker boxes
Sanders wrote:
Fine, tell my teachers that they didn't know what they were talking about. A post from Dick Pierce constitutes just that. Relay it to your teachers if what you posted is what they told you. Please learn the usenet posting style, you could be a very interesting contributor from what I have read of your posts. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#68
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Old speaker boxes
Sanders wrote:
Fine, tell my teachers that they didn't know what they were talking about. A post from Dick Pierce constitutes just that. Relay it to your teachers if what you posted is what they told you. Please learn the usenet posting style, you could be a very interesting contributor from what I have read of your posts. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#69
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Old speaker boxes
Sanders wrote:
Fine, tell my teachers that they didn't know what they were talking about. A post from Dick Pierce constitutes just that. Relay it to your teachers if what you posted is what they told you. Please learn the usenet posting style, you could be a very interesting contributor from what I have read of your posts. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#70
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Old speaker boxes
Sanders wrote:
Fine, tell my teachers that they didn't know what they were talking about. A post from Dick Pierce constitutes just that. Relay it to your teachers if what you posted is what they told you. Please learn the usenet posting style, you could be a very interesting contributor from what I have read of your posts. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#71
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Old speaker boxes
Sanders wrote:
I bow out from the group as my knowledge learned is useless. Why? - all that happened was that you learned something, stay and learn. John Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#72
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Old speaker boxes
Sanders wrote:
I bow out from the group as my knowledge learned is useless. Why? - all that happened was that you learned something, stay and learn. John Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#73
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Old speaker boxes
Sanders wrote:
I bow out from the group as my knowledge learned is useless. Why? - all that happened was that you learned something, stay and learn. John Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#74
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Old speaker boxes
Sanders wrote:
I bow out from the group as my knowledge learned is useless. Why? - all that happened was that you learned something, stay and learn. John Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#76
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#77
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#78
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#80
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Old speaker boxes
In article ,
(Bill Turner) wrote: YOU HAVE TO LEARN WHAT IS IMPORTANT TO THE GROUP. MANY HAVE LEARNED THINGS THAT ARE NOT TRUE IN THEIR QUEST FOR KNOWLEDGE. So it's what's important to the group that counts, and truth is irrelevant. Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ |
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