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.

I would be very interested in seeing you apply this research to
cartridges/phono cables/ phono preamps.

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.

"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?

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

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

On 20 Nov 2003 22:43:45 GMT, (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

IIRC, that's already done the rounds, and was reckoned by the AP users
to be residuals in the test gear, not anything to do with the cables.
Certainly, I've not seen anything above -140dBW in any cable I've run
through some very expensive Marconi Instruments spectrum analysers.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

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.

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.

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

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.

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

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

On 21 Nov 2003 16:14:08 GMT, (Stewart Pinkerton)
wrote:


IIRC, that's already done the rounds, and was reckoned by the AP users
to be residuals in the test gear, not anything to do with the cables.
Certainly, I've not seen anything above -140dBW in any cable I've run
through some very expensive Marconi Instruments spectrum analysers.

Reckoning is one thing. Actually doing the same measurement under the
same conditions as Curl (i.e. 30mV 1kHz stimulus with the fundamental
notched out) is another. And up to this point I wasn't aware of anyone
who had done anything along those lines.

Arny did some measurements with a 30mV 1kHz stimulus but didn't notch
out the fundamental so Curl dismissed his results saying that Arny's
plots weren't measuring as far down as his were. His measurements were
also taken to task for the high levels of noise and other spuriae in
the plots.

I'd tried to enlist the help of a couple of individuals with AP rigs
to try and duplicate Curl's results but they have yet had the time to
do them. So I was rather pleasantly surprised to come across Bruno's
post and better, his saying he'd made distortion measurements using a
stimulus whose magnitude was as low and lower than Curl's 30mV. And
using AP's latest System Two Cascade.

se

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

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

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

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).

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

Oops. His comments regarding the System Two Cascade wound up in the
thread below.

http://www.audioasylum.com/forums/pr...ages/6776.html

se

"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.

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

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.

(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

(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.

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

(Mkuller) wrote in message news:ZRgxb.236842$275.886690@attbi_s53...
(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

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.

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?

se

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.

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.

(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

On 27 Nov 2003 16:34:53 GMT, (Stuart Stebbings)
wrote:

(Mkuller) wrote in message news:ZRgxb.236842$275.886690@attbi_s53...
(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.

Not when you don't *know* which one is connected, you can't!

(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?

Because there *is* no audible difference?

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?

Yup, just like that one.................

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.

Perhaps you should first establish the existence of *real* audible
differences, before scrabbling around for measurements to explain
them. It's trivial to *measure* pretty large differences among cables,
but *audible* differences seem to be non-existent, except under the
most extreme cases of electrical difference.

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.

If you are using sighted listening, then it's much better possibility
that they are *not* real, for reasons given ad nauseam. Why is it that
you guys keep howling for us to 'trust our ears', and yet this is the
one thing that you refuse to do yourselves?

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.

What 'phenomenon'? That's the whole point - if you don't *know* which
cable is connected, then there simply *is* no audible difference among
cables, unless there is a *gross* electrical difference causing a dB
or more difference at the speaker terminals.

Until someone can demonstrate an ability to *hear* differences among
cables when they don't actually *know* which one is connected, then
there *is* no 'phenomenon', and hence no need to chase around looking
for exotic differences to explain it.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

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.

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

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

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

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.

"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.

(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.

(Steve Eddy) wrote in message news:D1Nxb.247859$275.907017@attbi_s53...


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.

I am. Only when one is intimately familiar with the sound of one's
system can one notice the slightest changes. The problem with much
testing is that the test subject is presented with two or more
variables, not one of which is he intimately familiar. When I listen
in MY system, I know what it sounds like already. The change is
blatantly obvious.