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#1
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Some serious cable measurements with interesting results.
Recently I've done a collection of measurements on interconnect cables to
see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up. "Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up. In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band). In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. Or will it? There's one well known (and usually ignored) effect in unbalanced connections, which is that the same conductor that connects the chassis also serves as reference to the signal. In a normal cable, these are 100% coupled, which means that the part of the chassis error voltage that drops across the inductive part of the cable impedance (end-to-end impedance of the shield) will couple into the conductor and be compensated 100% (Yes! Unbalanced connections have got CMRR in some way); However, lower frequencies will cause more voltage drop across the resistive component of the shield, and this appears as an error voltage at the receiving end. Take a coaxial cable and dress it in a number of extra layers of shield salvaged from other cables. Hear the sound improve... it addresses the same problem as "mains conditioners" but it does so much more effectively. The intelligent solution however, is to use balanced connections. This will remove this effect completely as the signal reference and chassis connection functions are separated. Next. There may not be a difference between what goes into a cable and what comes out, but this does not mean that the presence of the cable can't modify the signal. I'm talking about Microphonics of course. This has two causes, triboelectric charging and modulation of the voltage present on the cable. The former is the same effect that causes you to accumulate electric charge when walking across a thick carpet in winter. The charge is siphoned off to the terminating resistances of the cable (so it doesn't create crackling discharges), and creates a voltage there as long as the cable is moving. The latter is the same thing that makes condenser microphones work. The signal provides a constantly changing polarisation charge, and motion of the conductors will change the cable capacitance, also changing the voltage this charge represents. Applying a "bias voltage" as done by some cable companies in a bid to linearise the dielectric (this purported nonlinearity does not show up in any test) is extremely counterproductive in this respect! Reducing triboelectric charging is done by using a dielectric/conductor duo that produces little contact charge. Aluminium and paper are one such combination, cotton and steel another. Unfortunately, paper and especially cotton are quite soft, making the cable particularly susceptible to the condenser-mic effect. A method to reduce triboelectric noise in normal insulators consists of lubricating the shield/insulator interface with graphite. Reducing the condenser mic effect requires a tough (hard to deform) dielectric. Teflon is a famous example. Unfortunately, teflon is incredibly triboelectric against practically any other substance. In addition to this, the stiffness of teflon and also silver makes the cable nearly lossless, mechanically speaking. Measured microphonic impulse responses show tremendous ringing in the upper audio band. This could explain the "brightness" often attributed to silver/teflon cables. Again, there's the good engineering solution: use a signal source with as low as possible impedance. Charges generated and transferred because of either effect are absorbed at the source and the receiving end never gets to see it. Summing up: to make cables disappear from the sonic equation, all that is needed is balanced transmission combined with sub-1ohm output impedance line drivers. I would like to propose this as a standard for audiophile equipment makers. The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. |
#2
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Some serious cable measurements with interesting results.
I would be very interested in seeing you apply this research to
cartridges/phono cables/ phono preamps. |
#3
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Some serious cable measurements with interesting results.
While the science of this is basically beyond me, I am interested in the
cables that were tested and the outcome of this testing and how it relates to their "sonic" qualities. I have asked in the past, what is in those boxes attached to say, a MIT cable. I have been told a bunch of cheap resistors. Does that mean the MIT "dumbs down" their lower end cables? Then there is Audioquest with batteries included. All these at a price that makes one scratch his/her head if they are worth it outside of bragging rights. Bruno Putzeys wrote: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up. "Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up. In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band). In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. Or will it? There's one well known (and usually ignored) effect in unbalanced connections, which is that the same conductor that connects the chassis also serves as reference to the signal. In a normal cable, these are 100% coupled, which means that the part of the chassis error voltage that drops across the inductive part of the cable impedance (end-to-end impedance of the shield) will couple into the conductor and be compensated 100% (Yes! Unbalanced connections have got CMRR in some way); However, lower frequencies will cause more voltage drop across the resistive component of the shield, and this appears as an error voltage at the receiving end. Take a coaxial cable and dress it in a number of extra layers of shield salvaged from other cables. Hear the sound improve... it addresses the same problem as "mains conditioners" but it does so much more effectively. The intelligent solution however, is to use balanced connections. This will remove this effect completely as the signal reference and chassis connection functions are separated. Next. There may not be a difference between what goes into a cable and what comes out, but this does not mean that the presence of the cable can't modify the signal. I'm talking about Microphonics of course. This has two causes, triboelectric charging and modulation of the voltage present on the cable. The former is the same effect that causes you to accumulate electric charge when walking across a thick carpet in winter. The charge is siphoned off to the terminating resistances of the cable (so it doesn't create crackling discharges), and creates a voltage there as long as the cable is moving. The latter is the same thing that makes condenser microphones work. The signal provides a constantly changing polarisation charge, and motion of the conductors will change the cable capacitance, also changing the voltage this charge represents. Applying a "bias voltage" as done by some cable companies in a bid to linearise the dielectric (this purported nonlinearity does not show up in any test) is extremely counterproductive in this respect! Reducing triboelectric charging is done by using a dielectric/conductor duo that produces little contact charge. Aluminium and paper are one such combination, cotton and steel another. Unfortunately, paper and especially cotton are quite soft, making the cable particularly susceptible to the condenser-mic effect. A method to reduce triboelectric noise in normal insulators consists of lubricating the shield/insulator interface with graphite. Reducing the condenser mic effect requires a tough (hard to deform) dielectric. Teflon is a famous example. Unfortunately, teflon is incredibly triboelectric against practically any other substance. In addition to this, the stiffness of teflon and also silver makes the cable nearly lossless, mechanically speaking. Measured microphonic impulse responses show tremendous ringing in the upper audio band. This could explain the "brightness" often attributed to silver/teflon cables. Again, there's the good engineering solution: use a signal source with as low as possible impedance. Charges generated and transferred because of either effect are absorbed at the source and the receiving end never gets to see it. Summing up: to make cables disappear from the sonic equation, all that is needed is balanced transmission combined with sub-1ohm output impedance line drivers. I would like to propose this as a standard for audiophile equipment makers. The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. |
#4
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Some serious cable measurements with interesting results.
"Bruno Putzeys" wrote in message
news:B77vb.193311$mZ5.1434271@attbi_s54... Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up. "Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up. In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band). In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. Or will it? There's one well known (and usually ignored) effect in unbalanced connections, which is that the same conductor that connects the chassis also serves as reference to the signal. In a normal cable, these are 100% coupled, which means that the part of the chassis error voltage that drops across the inductive part of the cable impedance (end-to-end impedance of the shield) will couple into the conductor and be compensated 100% (Yes! Unbalanced connections have got CMRR in some way); However, lower frequencies will cause more voltage drop across the resistive component of the shield, and this appears as an error voltage at the receiving end. Take a coaxial cable and dress it in a number of extra layers of shield salvaged from other cables. Hear the sound improve... it addresses the same problem as "mains conditioners" but it does so much more effectively. The intelligent solution however, is to use balanced connections. This will remove this effect completely as the signal reference and chassis connection functions are separated. Next. There may not be a difference between what goes into a cable and what comes out, but this does not mean that the presence of the cable can't modify the signal. I'm talking about Microphonics of course. This has two causes, triboelectric charging and modulation of the voltage present on the cable. The former is the same effect that causes you to accumulate electric charge when walking across a thick carpet in winter. The charge is siphoned off to the terminating resistances of the cable (so it doesn't create crackling discharges), and creates a voltage there as long as the cable is moving. The latter is the same thing that makes condenser microphones work. The signal provides a constantly changing polarisation charge, and motion of the conductors will change the cable capacitance, also changing the voltage this charge represents. Applying a "bias voltage" as done by some cable companies in a bid to linearise the dielectric (this purported nonlinearity does not show up in any test) is extremely counterproductive in this respect! Reducing triboelectric charging is done by using a dielectric/conductor duo that produces little contact charge. Aluminium and paper are one such combination, cotton and steel another. Unfortunately, paper and especially cotton are quite soft, making the cable particularly susceptible to the condenser-mic effect. A method to reduce triboelectric noise in normal insulators consists of lubricating the shield/insulator interface with graphite. Reducing the condenser mic effect requires a tough (hard to deform) dielectric. Teflon is a famous example. Unfortunately, teflon is incredibly triboelectric against practically any other substance. In addition to this, the stiffness of teflon and also silver makes the cable nearly lossless, mechanically speaking. Measured microphonic impulse responses show tremendous ringing in the upper audio band. This could explain the "brightness" often attributed to silver/teflon cables. Again, there's the good engineering solution: use a signal source with as low as possible impedance. Charges generated and transferred because of either effect are absorbed at the source and the receiving end never gets to see it. Summing up: to make cables disappear from the sonic equation, all that is needed is balanced transmission combined with sub-1ohm output impedance line drivers. I would like to propose this as a standard for audiophile equipment makers. The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. Seems to me also to say that in practice, it is possible for single-ended cables to sound slightly different based on their shielding, construction materials, and wire material (silver). Is that not so? |
#5
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Some serious cable measurements with interesting results.
On Thu, 20 Nov 2003 17:48:17 GMT, "Bruno Putzeys"
wrote: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. You might be interested to know that John Curl claims to have measured distortion (of the harmonic variety) differences in interconnect cables, which he likes to say is evidence of the "micro diode" theory promoted by the likes of van den Hul. That is, micro diodes within the wire itself. He says that this distortion doesn't manifest itself at typical test levels but down around 30mV. And in order to achieve sufficient dynamic range to show the distortion products, the fundamental must be notched out (I mention this because Arny Krueger made some similar measurements but they were dismissed because he didn't notch out the fundamental). I'm wondering if you might be interested in seeing if you can duplicate Curl's results. His measurements were made using a modified late 70s vintage Sound Technologies rig and it would be interesting to see what results the same test would give on the System Two Cascade. The following FFT plots were made by Curl by feeding the post-notch output of his ST rig into his Macintosh's sound card using Mac The Scope FFT software and 100 averages. The cables are from Radio Shack (the worst), JPS Labs (next best) and van den Hul (the best) respectively. http://www.q-audio.com/images/rs.jpg http://www.q-audio.com/images/jps.jpg http://www.q-audio.com/images/vdh.jpg se |
#6
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Some serious cable measurements with interesting results.
On 20 Nov 2003 21:31:31 GMT, "Harry Lavo" wrote:
"Bruno Putzeys" wrote in message news:B77vb.193311$mZ5.1434271@attbi_s54... The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. Seems to me also to say that in practice, it is possible for single-ended cables to sound slightly different based on their shielding, construction materials, and wire material (silver). Is that not so? That's correct, except that silver makes no difference whatever, and the other electrical problems may be addressed by the use of industrial-grade cables which cost a maximum of $5 a metre. You might be surprised to learn that studio-grade mic cable and patch cable at a buck a foot is as good as it gets (Canare star-quad being about the ultimate). Of course, that *shouldn't* surprise anyone. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#8
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Some serious cable measurements with interesting results.
Seems to me also to say that in practice, it is possible for single-ended
cables to sound slightly different based on their shielding, construction materials, and wire material (silver). Is that not so? Indeed. It bothered me. I consider such a situation an engineering problem (others make money out of it), which is why I took it up. The message is that it's better to solve the problem by implementing correct I/O circuitry rather than treating the symptom. |
#9
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Some serious cable measurements with interesting results.
I might do it with a few individual parts (eg caps), but it's not something
I want to spend my life doing :-) "S888Wheel" wrote in message news:0n8vb.258185$Tr4.804144@attbi_s03... I would be very interested in seeing you apply this research to cartridges/phono cables/ phono preamps. |
#10
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Some serious cable measurements with interesting results.
Bruno Putzeys wrote [and I have shortened considerably --MHP]:
Recently I've done a collection of measurements on interconnect cables [...] Distortion: [...] There was no difference between the cables tested. Phase noise.[...] Nothing showed up. [...] In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. Or will it? There's one well known (and usually ignored) effect in unbalanced connections, which is that the same conductor that connects the chassis also serves as reference to the signal. Next. [...] Microphonics of course. OK, so you tested some items and then drew some hypotheses about two other possible issues. Why don't you test those! Mike Prager North Carolina, USA |
#11
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Some serious cable measurements with interesting results.
I haven't opened up an MIT yet so I can't tell what they are doing. The
AudioQuest story is a case of biasing the dielectric. The reasoning goes that the dielectric is nonlinear around zero field strength, and it is biased into a more favourable region. Few dielectrics are nonlinear. Those that are, are nonlinear at high field strengths (tens of kilovolts per centimeter), and are at their best around zero. The biasing may certainly change the sound by increasing microphonics. If the difference is detectable, it will be better without the bias. The sonic colouration relates reasonably well with the microphonics. I haven't got the full story yet because there is a significant difference between flexure (as in travelling waves) and pressure. Also, the acoustic impedance of any cable is very high (very stiff compared to air) so the frequency response is different between reception of air-borne sound and mechanically applied vibrations. All these things combine and make it difficult to draw a 1:1 relationship between the measurements and the sound. "TonyP" wrote in message news:Vk9vb.259857$Fm2.275491@attbi_s04... While the science of this is basically beyond me, I am interested in the cables that were tested and the outcome of this testing and how it relates to their "sonic" qualities. I have asked in the past, what is in those boxes attached to say, a MIT cable. I have been told a bunch of cheap resistors. Does that mean the MIT "dumbs down" their lower end cables? Then there is Audioquest with batteries included. All these at a price that makes one scratch his/her head if they are worth it outside of bragging rights. Bruno Putzeys wrote: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up. "Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up. In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band). In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. Or will it? There's one well known (and usually ignored) effect in unbalanced connections, which is that the same conductor that connects the chassis also serves as reference to the signal. In a normal cable, these are 100% coupled, which means that the part of the chassis error voltage that drops across the inductive part of the cable impedance (end-to-end impedance of the shield) will couple into the conductor and be compensated 100% (Yes! Unbalanced connections have got CMRR in some way); However, lower frequencies will cause more voltage drop across the resistive component of the shield, and this appears as an error voltage at the receiving end. Take a coaxial cable and dress it in a number of extra layers of shield salvaged from other cables. Hear the sound improve... it addresses the same problem as "mains conditioners" but it does so much more effectively. The intelligent solution however, is to use balanced connections. This will remove this effect completely as the signal reference and chassis connection functions are separated. Next. There may not be a difference between what goes into a cable and what comes out, but this does not mean that the presence of the cable can't modify the signal. I'm talking about Microphonics of course. This has two causes, triboelectric charging and modulation of the voltage present on the cable. The former is the same effect that causes you to accumulate electric charge when walking across a thick carpet in winter. The charge is siphoned off to the terminating resistances of the cable (so it doesn't create crackling discharges), and creates a voltage there as long as the cable is moving. The latter is the same thing that makes condenser microphones work. The signal provides a constantly changing polarisation charge, and motion of the conductors will change the cable capacitance, also changing the voltage this charge represents. Applying a "bias voltage" as done by some cable companies in a bid to linearise the dielectric (this purported nonlinearity does not show up in any test) is extremely counterproductive in this respect! Reducing triboelectric charging is done by using a dielectric/conductor duo that produces little contact charge. Aluminium and paper are one such combination, cotton and steel another. Unfortunately, paper and especially cotton are quite soft, making the cable particularly susceptible to the condenser-mic effect. A method to reduce triboelectric noise in normal insulators consists of lubricating the shield/insulator interface with graphite. Reducing the condenser mic effect requires a tough (hard to deform) dielectric. Teflon is a famous example. Unfortunately, teflon is incredibly triboelectric against practically any other substance. In addition to this, the stiffness of teflon and also silver makes the cable nearly lossless, mechanically speaking. Measured microphonic impulse responses show tremendous ringing in the upper audio band. This could explain the "brightness" often attributed to silver/teflon cables. Again, there's the good engineering solution: use a signal source with as low as possible impedance. Charges generated and transferred because of either effect are absorbed at the source and the receiving end never gets to see it. Summing up: to make cables disappear from the sonic equation, all that is needed is balanced transmission combined with sub-1ohm output impedance line drivers. I would like to propose this as a standard for audiophile equipment makers. The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. |
#12
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Some serious cable measurements with interesting results.
The AP's THD measurements work the same way - removing the fundamental
leaving the rest for analysis. I have indeed done low-level distortion tests (down to several uV), to no avail. The levels he's reporting are very high, much higher than what is found with most amplifiers. I cannot tell what caused the distortion in his test, but it didn't happen here. Quite likely the ground loop between the distortion analyser and the computer is to blame (the former having a grounded output and the latter having a grounded input), in which case the shield resistance would be a factor. The distortion was certainly not generated in the cable itself. "Steve Eddy" wrote in message ... You might be interested to know that John Curl claims to have measured distortion (of the harmonic variety) differences in interconnect cables, which he likes to say is evidence of the "micro diode" theory promoted by the likes of van den Hul. That is, micro diodes within the wire itself. He says that this distortion doesn't manifest itself at typical test levels but down around 30mV. And in order to achieve sufficient dynamic range to show the distortion products, the fundamental must be notched out (I mention this because Arny Krueger made some similar measurements but they were dismissed because he didn't notch out the fundamental). I'm wondering if you might be interested in seeing if you can duplicate Curl's results. His measurements were made using a modified late 70s vintage Sound Technologies rig and it would be interesting to see what results the same test would give on the System Two Cascade. The following FFT plots were made by Curl by feeding the post-notch output of his ST rig into his Macintosh's sound card using Mac The Scope FFT software and 100 averages. The cables are from Radio Shack (the worst), JPS Labs (next best) and van den Hul (the best) respectively. http://www.q-audio.com/images/rs.jpg http://www.q-audio.com/images/jps.jpg http://www.q-audio.com/images/vdh.jpg se |
#13
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Some serious cable measurements with interesting results.
On Fri, 21 Nov 2003 16:19:17 GMT, "Bruno Putzeys"
wrote: The AP's THD measurements work the same way - removing the fundamental leaving the rest for analysis. Well, they can be done that way. More typically I see them done with the fundamental left in. I have indeed done low-level distortion tests (down to several uV), to no avail. The levels he's reporting are very high, much higher than what is found with most amplifiers. I cannot tell what caused the distortion in his test, but it didn't happen here. Ok. Quite likely the ground loop between the distortion analyser and the computer is to blame (the former having a grounded output and the latter having a grounded input), in which case the shield resistance would be a factor. Mmmm. How exactly would a ground loop produce all those harmonics of the 1kHz stimulus? The distortion was certainly not generated in the cable itself. That's what I've been trying to verify. Thanks. se |
#14
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Some serious cable measurements with interesting results.
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#15
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Some serious cable measurements with interesting results.
Bruno Putzeys wrote:
[...] Again, there's the good engineering solution: use a signal source with as low as possible impedance. Charges generated and transferred because of either effect are absorbed at the source and the receiving end never gets to see it. Summing up: to make cables disappear from the sonic equation, all that is needed is balanced transmission combined with sub-1ohm output impedance line drivers. I would like to propose this as a standard for audiophile equipment makers. Bruno, Where in the world did you get value "sub-1 ohm"? Yes, lower is better from an electrical point of view, but there are practical issues. What engineering criteria could be used to rationally establish an upper limit to the output impedance specification? Seems like the maximum current we're likely to see from the various sources, along with a maximum resulting voltage error, would establish the maximum required output impedance in a rational way. However, I have no idea what thoses maximums would be. By the way, accolades to you for taking the time and initiative to do this testing. Your results do not surprise me in the least, and it is great to see good, solid engineering expertise applied to this issue. -- % Randy Yates % "...the answer lies within your soul %% Fuquay-Varina, NC % 'cause no one knows which side %%% 919-577-9882 % the coin will fall." %%%% % 'Big Wheels', *Out of the Blue*, ELO http://home.earthlink.net/~yatescr |
#16
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Some serious cable measurements with interesting results.
On Fri, 21 Nov 2003 16:19:17 GMT, "Bruno Putzeys"
wrote: The AP's THD measurements work the same way - removing the fundamental leaving the rest for analysis. I have indeed done low-level distortion tests (down to several uV), to no avail. The levels he's reporting are very high, much higher than what is found with most amplifiers. I cannot tell what caused the distortion in his test, but it didn't happen here. Quite likely the ground loop between the distortion analyser and the computer is to blame (the former having a grounded output and the latter having a grounded input), in which case the shield resistance would be a factor. The distortion was certainly not generated in the cable itself. By the way, I passed this all along to John Curl and he's dismissed your measurements saying that the Audio Precision System Two Cascade's distortion measurement capabilities aren't able to match the resolution of his 25 year old Sound Technologies 1700B feeding a separate spectrum analyzer (which includes his Mac's sound card using Mac The Scope software). He says he's upgraded the opamps in the 1700B but I find it a bit hard to believe that Audio Precision's most advanced measurement system can't even equal let alone exceed a 25 year old distortion analyzer (even with upgraded opamps) and a built-in computer sound card. You may find Curl's remarks on this issue he http://www.audioasylum.com/forums/pr...ages/6780.html se |
#17
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Some serious cable measurements with interesting results.
That's correct, except that silver makes no difference whatever, and
the other electrical problems may be addressed by the use of industrial-grade cables which cost a maximum of $5 a metre. Not quite. The microphonics were tested on good cable too. A low source impedance is also required to get rid of that problem. Good cable is not enough. Once you've got low-impedance drive (and balanced wiring) the standard cable should do. At least that's what I'm contending :-) As for silver, if the insulation is Teflon, triboelectricity is a tiny bit less if the conductor is silver(ed) compared to copper. Having said that, the most spectacularly microphonic cable I've ever tested was a teflon/silver coax. It appears teflon is out of the running for serious use, unless you like to use acoustic feedback to colour the sound. "Stewart Pinkerton" wrote in message ... On 20 Nov 2003 21:31:31 GMT, "Harry Lavo" wrote: "Bruno Putzeys" wrote in message news:B77vb.193311$mZ5.1434271@attbi_s54... The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. Seems to me also to say that in practice, it is possible for single-ended cables to sound slightly different based on their shielding, construction materials, and wire material (silver). Is that not so? That's correct, except that silver makes no difference whatever, and the other electrical problems may be addressed by the use of industrial-grade cables which cost a maximum of $5 a metre. You might be surprised to learn that studio-grade mic cable and patch cable at a buck a foot is as good as it gets (Canare star-quad being about the ultimate). Of course, that *shouldn't* surprise anyone. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#18
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Some serious cable measurements with interesting results.
OK, so you tested some items and then drew some hypotheses
about two other possible issues. Why don't you test those! Exactly the plan. The shield issue is something you can try out for yourself. The difference is startling (in cable terms), and needs little further proof. Again, have a shot at modifying an existing coax using extra shields and hear for yourself. For microphonics, the idea is to take (or if necessary, make) 1) Two [sets of] cables of very different construction but very low microphonics. 2) Two cables as identical as possible in construction but different in microphonics. This can be done using one cable with graphite lubrication between shield and insulator and one cable without. I would expect such two cable types to be directly available from Belden. For this test, balanced connection with a normal drive impedance (50 to 100 ohms) will be used, in order to eliminate the shield issue witout affecting the microphonic problem under test. The same test will then be redone using low drive impedance (1 ohm). |
#19
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Some serious cable measurements with interesting results.
Admittedly the sub 1ohm value is somewhat arbitrary. The reason was that at
the 20 ohm setting of the AP2, microphonics were still detectable (noise floor around 7nV/rtHz). So I "sez" to myself let's undercut this 20 ohm figure with a margin. Now I'm designing a "universal" (ie floating) balanced line driver to match the specs I put forward. These specs also include unconditional stability and low distortion (1ppm at 20kHz). It is a bit challenging but the spice simulations look promising. Bruno, Where in the world did you get value "sub-1 ohm"? Yes, lower is better from an electrical point of view, but there are practical issues. What engineering criteria could be used to rationally establish an upper limit to the output impedance specification? Seems like the maximum current we're likely to see from the various sources, along with a maximum resulting voltage error, would establish the maximum required output impedance in a rational way. However, I have no idea what thoses maximums would be. By the way, accolades to you for taking the time and initiative to do this testing. Your results do not surprise me in the least, and it is great to see good, solid engineering expertise applied to this issue. -- % Randy Yates % "...the answer lies within your soul %% Fuquay-Varina, NC % 'cause no one knows which side %%% 919-577-9882 % the coin will fall." %%%% % 'Big Wheels', *Out of the Blue*, ELO http://home.earthlink.net/~yatescr |
#20
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Some serious cable measurements with interesting results.
Oops. His comments regarding the System Two Cascade wound up in the
thread below. http://www.audioasylum.com/forums/pr...ages/6776.html se |
#21
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Some serious cable measurements with interesting results.
"Bruno Putzeys" wrote in message news:B77vb.193311$mZ5.1434271@attbi_s54...
The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. |
#22
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Some serious cable measurements with interesting results.
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#23
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Some serious cable measurements with interesting results.
Bruce wrote:
Engineers can show that the wire itself can't distort an audio signal unless it is very long and/or has an exceptionally small guage. However, it is possible that a good cable's small, inherent inductance may interact with an amplifier's feedback loop and create marginal instability or ultrasonic ringing. Depending on the amplifier and speakers, that oscillation or ringing may have subtle audible consequences. In such a case, would you blame the cable or the amplifier? I would blame the amplifier- the problem should be avoidable through good circuit design. There isn't an excuse for such behaviour in modern amps, but back when the bandwidth of power transistors was more limited, it was often unavoidable if the designer wanted to maintain feedback ratios at high frequencies to keep distortion down. |
#24
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Some serious cable measurements with interesting results.
(Michael
Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. (Steve Eddy) wrote: But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. Like the claim of most amplifiers sounding different? That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? I guess it depends on what you consider "clear and convincing evidence". If you're looking for measurements that relate to the audible differences, perhaps Mike Scarpitti is correct and you are measuring the wrong things. If it's dbts you're looking for as proof, there is no actual scientific evidence they work on open-ended audio equipment comparisons with music without getting in the way of subtle audible differences, in spite of all those who protest to the contrary. So if you hear audible differences between cables (or amps), it's a good possibility they are real. Regards, Mike |
#25
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Some serious cable measurements with interesting results.
(Steve Eddy) wrote in message ...
On Wed, 26 Nov 2003 00:52:07 GMT, (Michael Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? Decades ago we were able to show clear and convincing evidence establishing the existence of subatomic particles. Yet simply establishing actual audiblilty of cable differences seems to be even more elusive. se It's not elusive. I bought Monster $50 cables (interconnect) a few years ago. I then bought $100 Monster cables. I then switched them in and out of my system several times. The difference was subtle, but consistent. The more expensive cable offered deeper bass and better imaging, with better clarity on transients as well. Every time. The difference was much more apparent when I removed the more expensive ones and replaced the cheaper ones into the system: the deterioration in the sound was quite obvious. This phenomenon also calls for explanation. |
#26
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Some serious cable measurements with interesting results.
On Thu, 27 Nov 2003 06:36:05 GMT, (Michael
Scarpitti) wrote: (Steve Eddy) wrote in message ... On Wed, 26 Nov 2003 00:52:07 GMT, (Michael Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? Decades ago we were able to show clear and convincing evidence establishing the existence of subatomic particles. Yet simply establishing actual audiblilty of cable differences seems to be even more elusive. se It's not elusive. I bought Monster $50 cables (interconnect) a few years ago. I then bought $100 Monster cables. I then switched them in and out of my system several times. The difference was subtle, but consistent. The more expensive cable offered deeper bass and better imaging, with better clarity on transients as well. Every time. The difference was much more apparent when I removed the more expensive ones and replaced the cheaper ones into the system: the deterioration in the sound was quite obvious. This phenomenon also calls for explanation. But that's simply your sighted, subjective perception which is known to be unreliable and doesn't in itself establish actual audibility. It only establishes that you subjectively perceived some difference. If you read my reply to Mkuller I mentioned that people have reported hearing significant improvements in their systems after placing photographs of themselves and their equipment in their freezers. So does this constitute clear and convincing evidence that placing photographs in our freezers produces actual audible differences? se |
#27
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Some serious cable measurements with interesting results.
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#28
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Some serious cable measurements with interesting results.
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#29
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Some serious cable measurements with interesting results.
Steve Eddy wrote:
On Thu, 20 Nov 2003 17:48:17 GMT, "Bruno Putzeys" wrote: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. You might be interested to know that John Curl claims to have measured distortion (of the harmonic variety) differences in interconnect cables, which he likes to say is evidence of the "micro diode" theory promoted by the likes of van den Hul. That is, micro diodes within the wire itself. He says that this distortion doesn't manifest itself at typical test levels but down around 30mV. And in order to achieve sufficient dynamic range to show the distortion products, the fundamental must be notched out (I mention this because Arny Krueger made some similar measurements but they were dismissed because he didn't notch out the fundamental). I'm wondering if you might be interested in seeing if you can duplicate Curl's results. His measurements were made using a modified late 70s vintage Sound Technologies rig and it would be interesting to see what results the same test would give on the System Two Cascade. The following FFT plots were made by Curl by feeding the post-notch output of his ST rig into his Macintosh's sound card using Mac The Scope FFT software and 100 averages. The cables are from Radio Shack (the worst), JPS Labs (next best) and van den Hul (the best) respectively. http://www.q-audio.com/images/rs.jpg http://www.q-audio.com/images/jps.jpg http://www.q-audio.com/images/vdh.jpg se Mr. Curl's measurement results are highly unexpected, to say the least. One thing that comes to mind is that he is using a sampling scheme. If the sampling frequency is exactly a multiple of the fundamental, in this case 1 KHz, certain sampling artifacts may appear as harmonic distortion. I would recommend that he moves the fundamental frequency to something like 950 Hz on the Sound Technology 1700B, and repeat the measurements. He may find that the spurious signals now are no longer at harmonics of the fundamental. This is what I would do first. Another thing worth trying is borrowing an analog audio spectrum analyzer and look at the residuals at the output of the ST1700. I have done that many times, and I do not recall ever seeing the comb lines that he saw. Also, he should try to put an amplifier in front of the sound card, like a 20dB amp for example. If the distortion components do not go up by 20dB, we can be sure that they come from the sound card and not caused by the cable. |
#30
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Some serious cable measurements with interesting results.
Steve Eddy wrote:
On Thu, 27 Nov 2003 06:30:17 GMT, (Mkuller) wrote: (Michael Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. (Steve Eddy) wrote: But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. Like the claim of most amplifiers sounding different? Sure, you can lump that in as well if you like. That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? I guess it depends on what you consider "clear and convincing evidence". If you're looking for measurements that relate to the audible differences, perhaps Mike Scarpitti is correct and you are measuring the wrong things. Well, I don't see what good measurements are until it's first been established that there is in fact is some audible difference. If the perception is solely due to psychological phenomena, you can measure from now 'til Doomsday and not get anywhere. If it's dbts you're looking for as proof, there is no actual scientific evidence they work on open-ended audio equipment comparisons with music without getting in the way of subtle audible differences, in spite of all those who protest to the contrary. So if you hear audible differences between cables (or amps), it's a good possibility they are real. Why is it a good possibility that they are real when it's been well established for quite some time that differences can be perceived even in the absence of any actual difference? People have reported significant improvements in the sound of their sytems (and, strangely enough, every other system they listen to) by placing photographs of themselves and their equipment in their freezers. Carol Clark wrote about this Peter Belt tweak in audioMUSINGS and others have reported hearing similar differences/improvements. So does this mean that it's a good possibility that placing photographs of ourselves and our equipment in our freezers really does have a physical effect (Belt claims that this is a quantum mechanical effect) that we're able to perceive? The idea that everything we 'hear' is due to acoustic stimuli is patently absurd. It's akin to claiming that people have no auditory imagination, which if true would be very sad. Fortunately, it isn't. |
#31
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Some serious cable measurements with interesting results.
(Stuart Stebbings) wrote:
Mike You are not answering the central point We can measure things like sub atomic particles we can measure minute tremors in the earths surface after an earthquake many many thousands of miles away. Why can we not measure something as simple as a cable and the various parameters that make up an audio signal. If as you claim cables do have a different sound, do you think the manufacturer knows why? Would they have constructed the product knowing that doing "x" will give better bass response etc etc. If so how do they know this? How did they first find out about it.? Do you think they were doing R&D and found it out. I just dont believe that we are not able to measure this phenomenon. Stuart, I didn't say we are not able to measure these things. I said If you're looking for measurements that relate to the audible differences, perhaps Mike Scarpitti is correct and you are measuring the wrong things. Here on RAHE, most of the engineers will tell you the only measurements that matter with cables are R, L and C. If you talk to high end cable designers they will talk about their more sophisticated models of measurements that correlate to their designs. Some of it is marketing hype, but the fact that they can tailor the sound of the cables shows there might be something to it. I'll leave it to the engineers to read their "white papers" and try to provide an explanation that is easy to understand. In the mean time, like many audiophiles, I will listen and compare the sound of the cables before I buy them. Regards, Mike |
#32
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Some serious cable measurements with interesting results.
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#33
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ERRATUM Some serious cable measurements with interesting results.
ERRATUM
The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. Should read: "The above shows that people who claim that cables do NOT make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right." My apologies to those who feel they belong to one "camp" and are now suddenly yanked into another. |
#34
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Some serious cable measurements with interesting results.
On Fri, 28 Nov 2003 07:58:34 GMT, chung wrote:
Steve Eddy wrote: On Thu, 20 Nov 2003 17:48:17 GMT, "Bruno Putzeys" wrote: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. You might be interested to know that John Curl claims to have measured distortion (of the harmonic variety) differences in interconnect cables, which he likes to say is evidence of the "micro diode" theory promoted by the likes of van den Hul. That is, micro diodes within the wire itself. He says that this distortion doesn't manifest itself at typical test levels but down around 30mV. And in order to achieve sufficient dynamic range to show the distortion products, the fundamental must be notched out (I mention this because Arny Krueger made some similar measurements but they were dismissed because he didn't notch out the fundamental). I'm wondering if you might be interested in seeing if you can duplicate Curl's results. His measurements were made using a modified late 70s vintage Sound Technologies rig and it would be interesting to see what results the same test would give on the System Two Cascade. The following FFT plots were made by Curl by feeding the post-notch output of his ST rig into his Macintosh's sound card using Mac The Scope FFT software and 100 averages. The cables are from Radio Shack (the worst), JPS Labs (next best) and van den Hul (the best) respectively. http://www.q-audio.com/images/rs.jpg http://www.q-audio.com/images/jps.jpg http://www.q-audio.com/images/vdh.jpg se Mr. Curl's measurement results are highly unexpected, to say the least. Yes. Certainly it's known that poor contacts can cause nonlinearities, but John seems to believe that this distortion is being produced by the wire itself, something he said he was first turned on to by A.J. van den Hul who according to John did similar measurements over 20 years ago using just as old equipment. Van den Hul attributes this to "micro diodes" in the copper wire. I've been skeptical of these measurements, or rather the notion that it's being caused by the wire because while I can see how it MIGHT have escaped notice of the audio community I thought it rather odd that such non-linear behavior would have seemingly wholly escaped the materials science researchers all these years. One would think that if copper wire exhibited such non-linear behavior at the levels John is measuring, that it would have been well documented in the literature by now. But I haven't been able to find any evidence that it has. One thing that comes to mind is that he is using a sampling scheme. If the sampling frequency is exactly a multiple of the fundamental, in this case 1 KHz, certain sampling artifacts may appear as harmonic distortion. I would recommend that he moves the fundamental frequency to something like 950 Hz on the Sound Technology 1700B, and repeat the measurements. He may find that the spurious signals now are no longer at harmonics of the fundamental. This is what I would do first. Another thing worth trying is borrowing an analog audio spectrum analyzer and look at the residuals at the output of the ST1700. I have done that many times, and I do not recall ever seeing the comb lines that he saw. Also, he should try to put an amplifier in front of the sound card, like a 20dB amp for example. If the distortion components do not go up by 20dB, we can be sure that they come from the sound card and not caused by the cable. Thanks for the advice. However I should mention that John says that he has done the same measurements using a variety of spectrum analyzers including an analog model and essentially gets the same results. So it wouldn't appear to be due to the spectrum analyzer. So if it's an equipment problem (or just simple equipment limitations) it would appear to be in the 1700B. The reason I only mentioned the Mac sound card and Mac The Scope software is because the plots I provided are the only plots publically available (all else is just John's own accounts) and those were done with that combination. se |
#35
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Some serious cable measurements with interesting results.
On Fri, 28 Nov 2003 08:03:36 GMT, wrote:
Steve Eddy wrote: On Thu, 27 Nov 2003 06:30:17 GMT, (Mkuller) wrote: (Michael Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. (Steve Eddy) wrote: But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. Like the claim of most amplifiers sounding different? Sure, you can lump that in as well if you like. That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? I guess it depends on what you consider "clear and convincing evidence". If you're looking for measurements that relate to the audible differences, perhaps Mike Scarpitti is correct and you are measuring the wrong things. Well, I don't see what good measurements are until it's first been established that there is in fact is some audible difference. If the perception is solely due to psychological phenomena, you can measure from now 'til Doomsday and not get anywhere. If it's dbts you're looking for as proof, there is no actual scientific evidence they work on open-ended audio equipment comparisons with music without getting in the way of subtle audible differences, in spite of all those who protest to the contrary. So if you hear audible differences between cables (or amps), it's a good possibility they are real. Why is it a good possibility that they are real when it's been well established for quite some time that differences can be perceived even in the absence of any actual difference? People have reported significant improvements in the sound of their sytems (and, strangely enough, every other system they listen to) by placing photographs of themselves and their equipment in their freezers. Carol Clark wrote about this Peter Belt tweak in audioMUSINGS and others have reported hearing similar differences/improvements. So does this mean that it's a good possibility that placing photographs of ourselves and our equipment in our freezers really does have a physical effect (Belt claims that this is a quantum mechanical effect) that we're able to perceive? The idea that everything we 'hear' is due to acoustic stimuli is patently absurd. It's akin to claiming that people have no auditory imagination, which if true would be very sad. Fortunately, it isn't. Yes. There's a considerable amount of psychology behind our aural perceptions. Yet even when you can get some people to even acknowledge this fact, they insist that they're somehow immune. se |
#36
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Some serious cable measurements with interesting results.
On Fri, 28 Nov 2003 08:03:36 GMT, wrote:
Steve Eddy wrote: On Thu, 27 Nov 2003 06:30:17 GMT, (Mkuller) wrote: (Michael Scarpitti) wrote: If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. (Steve Eddy) wrote: But why, in the over 20 years that this claim has been made, has no one yet been able to demonstrate this to actually be the case? It's just one more empty claim to be tossed upon the mountain of empty claims that have been made for so many years. Like the claim of most amplifiers sounding different? Sure, you can lump that in as well if you like. That's not to say that it's impossible for there to be actual audible differences. But why has there not been any clear and convincing evidence of this by now? I guess it depends on what you consider "clear and convincing evidence". If you're looking for measurements that relate to the audible differences, perhaps Mike Scarpitti is correct and you are measuring the wrong things. Well, I don't see what good measurements are until it's first been established that there is in fact is some audible difference. If the perception is solely due to psychological phenomena, you can measure from now 'til Doomsday and not get anywhere. If it's dbts you're looking for as proof, there is no actual scientific evidence they work on open-ended audio equipment comparisons with music without getting in the way of subtle audible differences, in spite of all those who protest to the contrary. So if you hear audible differences between cables (or amps), it's a good possibility they are real. Why is it a good possibility that they are real when it's been well established for quite some time that differences can be perceived even in the absence of any actual difference? People have reported significant improvements in the sound of their sytems (and, strangely enough, every other system they listen to) by placing photographs of themselves and their equipment in their freezers. Carol Clark wrote about this Peter Belt tweak in audioMUSINGS and others have reported hearing similar differences/improvements. So does this mean that it's a good possibility that placing photographs of ourselves and our equipment in our freezers really does have a physical effect (Belt claims that this is a quantum mechanical effect) that we're able to perceive? The idea that everything we 'hear' is due to acoustic stimuli is patently absurd. It's akin to claiming that people have no auditory imagination, which if true would be very sad. Fortunately, it isn't. Yes. There's a considerable amount of psychology behind our aural perceptions. Yet even when you can get some people to even acknowledge this fact, they insist that they're somehow immune. se |
#37
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Some serious cable measurements with interesting results.
Misunderstanding caused by typo (see message marked Erratum). As I outline
in the original text, I hear these differences too. Unfortunately the conclusion was typographically disabled from correctly conveying the meaning of the rest of the text. "Michael Scarpitti" wrote in message news:XOSwb.304198$HS4.2716225@attbi_s01... "Bruno Putzeys" wrote in message news:B77vb.193311$mZ5.1434271@attbi_s54... The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. If your tests doesn't show differences, and I can hear differences, you're testing the wrong things. I can hear differences between cables. |
#38
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ERRATUM Some serious cable measurements with interesting results.
"Bruno Putzeys" wrote in message ...
ERRATUM The above shows that people who claim that cables do make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right. Should read: "The above shows that people who claim that cables do NOT make a difference are living on another planet. However, those that say that cables *should* not make a difference when correctly used, are dead right." My apologies to those who feel they belong to one "camp" and are now suddenly yanked into another. Huh? It's even worse now. Are you saying cable differences can be heard or not? I say yes. From this I cannot tell how you stand. |
#39
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Some serious cable measurements with interesting results.
(Stuart Stebbings) wrote in message ...
(Mkuller) wrote in message news:ZRgxb.236842$275.886690@attbi_s53... Mike You are not answering the central point We can measure things like sub atomic particles we can measure minute tremors in the earths surface after an earthquake many many thousands of miles away. But that isn't the same thing as measuring my heartrate. It could be going up or down while you're measuring something else. I went to my internist and told him I didn't feel well. I suggested he measure my testosterone levels. He pooh-poohed the idea, and said that was very unlikely. He tested me for diabetes, liver problems, anemia, etc., telling me these were FAR more likely. The results came back negative for all of them. Finally, I asked him again him to test my testosterone level. It measured low. I was right all along. Why can we not measure something as simple as a cable and the various parameters that make up an audio signal. Not what matters, apparently. If as you claim cables do have a different sound, do you think the manufacturer knows why? Not necessarily. Would they have constructed the product knowing that doing "x" will give better bass response etc etc. If so how do they know this? Trial and error. How did they first find out about it.? Do you think they were doing R&D and found it out. I just dont believe that we are not able to measure this phenomenon. |
#40
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Some serious cable measurements with interesting results.
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