Effects of Inductance and Skin-effect in a speaker wire.

[Tony_Montana]

As far as sonic effects of inductance and Skin effect is concern, there are alot of debate about this issue that will make your head to spin. But how about effect of above issues theoretically-such as phase shift and Group (frequency) Delay distortion?

Here is sample picture of an audio wave:



As one can see, these type of signals have alot of [upper frequency] harmonics, accompanied with lower frequency. The question is since higher frequency(s) will be more subject to cable's Inductance* and Skin effects*, then wouldn't that cause the higher frequency to shift/attenuate more from its original place on the signal (as compared with lower frequency) causing distortion or signal deformation?

Shouldn't we look for cables [beyond zip cord] that will address these issues also such as twisted cables (inductance), and make cable insulated strands less than 20 gauge size (skin effect)?
Or should we say that since these effects are not audible, then it should be ignored?

*Inductance:cable inductance is frequency dependable. Its effect will be higher as frequency increases causing higher frequency to attenuate and shift more than lower frequency(s).
*Skin Effect:This is also frequency dependable. As frequency increases, it will occupy less [area] space in a conductor causing higher frequency to be more subject to cable's resistance than lower frequency are.

[mtrycraft]

As far as sonic effects of inductance and Skin effect is concern, there are alot of debate about this issue that will make your head to spin. But how about effect of above issues theoretically-such as phase shift and Group (frequency) Delay distortion?

Here is sample picture of an audio wave:



As one can see, these type of signals have alot of [upper frequency] harmonics, accompanied with lower frequency. The question is since higher frequency(s) will be more subject to cable's Inductance* and Skin effects*, then wouldn't that cause the higher frequency to shift/attenuate more from its original place on the signal (as compared with lower frequency) causing distortion or signal deformation?

Shouldn't we look for cables [beyond zip cord] that will address these issues also such as twisted cables (inductance), and make cable insulated strands less than 20 gauge size (skin effect)?
Or should we say that since these effects are not audible, then it should be ignored?

*Inductance:cable inductance is frequency dependable. Its effect will be higher as frequency increases causing higher frequency to attenuate and shift more than lower frequency(s).
*Skin Effect:This is also frequency dependable. As frequency increases, it will occupy less [area] space in a conductor causing higher frequency to be more subject to cable's resistance than lower frequency are.

"Amplifier-Loudspeaker Interfacing", Greiner, R.A., JAES vol. 28, no. 5 May 80, page 310-315.


RA Greiner discusses the issue of group delay due to skin effects between 100Hz and 10kHz. I would not worry about a 1x 10 to -8 power sec.

Phase angle of 3 degrees at 20kHz if you can hear 20kHz is nothing.

"Effects of cable, Loudspeaker and Amplifier Interactions", Davis, Fred E., JAES, vol. 39, no. 6 Jun 91,

Davis calculated a .04dB loss due to skin effect at 20kHz.

Again, one must be able to detect 20kHz and second, one must have a Just noticable threshold this low on top of it.
But, JND has been measured at 16kHz to be about 3dB on average. This is of course much more than one would detect closer to the midbands where out acuity is much better.

Again, th egolden ears make much about nothing as they have too much time on hand to worry about nothing. That is not their fault mostly as the high end audio industry marketing has done a good job of voodoo magic and human gullibility has jumped on it. No different that anything else in consumer land.

Just reading an article on immunization for whooping cough over the past number of decades. Some raised alarms over the negative effects of immunization. Gullible people followed and the rate of whooping cough skyrocketed again.

[FLZapped]

"Amplifier-Loudspeaker Interfacing", Greiner, R.A., JAES vol. 28, no. 5 May 80, page 310-315.

RA Greiner discusses the issue of group delay due to skin effects between 100Hz and 10kHz. I would not worry about a 1x 10 to -8 power sec.

Phase angle of 3 degrees at 20kHz if you can hear 20kHz is nothing.

"Effects of cable, Loudspeaker and Amplifier Interactions", Davis, Fred E., JAES, vol. 39, no. 6 Jun 91,

Davis calculated a .04dB loss due to skin effect at 20kHz.

I calculated 0.03dB additional loss due to skin effect for a 10 foot run of 12 AWG cable at 20kHz.

As for phase shift, power amplifiers have more than the 3 degrees and no one ever says boo about that! (Although outside of pro amps, this is usually not a published spec)

Here is a refrence that talks about group delay in loudspeakers. Keep in mind that your speaker cable has a group delay in the hundreds of nano-seconds (10E-09)

http://www.trueaudio.com/post_010.htm

Here is a reference where the phase shift and group delay are talked about in wire and where the number I used above came from:

http://www.st-andrews.ac.uk/~www_pa/...eshift/cp.html

-Bruce

[mtrycraft]

I calculated 0.03dB additional loss due to skin effect for a 10 foot run of 12 AWG cable at 20kHz.

As for phase shift, power amplifiers have more than the 3 degrees and no one ever says boo about that! (Although outside of pro amps, this is usually not a published spec)

Here is a refrence that talks about group delay in loudspeakers. Keep in mind that your speaker cable has a group delay in the hundreds of nano-seconds (10E-09)

http://www.trueaudio.com/post_010.htm

Here is a reference where the phase shift and group delay are talked about in wire and where the number I used above came from:

http://www.st-andrews.ac.uk/~www_pa/...eshift/cp.html

-Bruce

Oh, sucks. I don't know if we can accept that .01dB difference
Maybe a different cable gauge?

[markw]

With all this talk about what wires and cables does to an electrical signal, hoccum nobody ever brings up what a transducer (such as a speaker) does to it?

That's kinda like refusing to go to a hospital 'cause you're wearing yesterday's underpants when you've just suffered several gunshots to the torso.

[mtrycraft]

With all this talk about what wires and cables does to an electrical signal, hoccum nobody ever brings up what a transducer (such as a speaker) does to it?
.

Because then they would have nothing to talk about or worry about
Then, all their pet voodoo nonsense would go uo in smoke and they would have to eat crow, lots of it.

[E-Stat]

With all this talk about what wires and cables does to an electrical signal, hoccum nobody ever brings up what a transducer (such as a speaker) does to it?

Look near the top of your computer screen. This is the Cables Forum. You will also find a Speaker Forum.

rw

[FLZapped]

Oh, sucks. I don't know if we can accept that .01dB difference
Maybe a different cable gauge?

Oh, I forgot, JR can hear the difference....-b

[jneutron]

A #12 zip, at .2 microhenries per foot, will store 2.5 uJoules per foot under a 100 wrms signal into 8 ohms. The same zip, with total and complete skinning, will store 2.0 uJoules per foot.

A 10 foot cable, will be capable of shedding 5 ujoules (absolute maximum) if the audio changes from lf to hf content during a waveform peak.

At 10Khz, that is .4% of the load energy of one cycle lobe. That is also a .2 uSec, or 200 nanosecond, leading edge delay and trailing edge advance. (simplistic calculation of integral of energy from one half cycle)

What does an amplifier do if wire stored energy tries to dump in during high slew rate signals?

Transducers will have an effect on what we hear (duh), but if the wires can cause different delays because they see different signals, the soundstage will shift, or blur, or whatever..

Question is...are the energy numbers large enough to be significant? Can the amp have a problem with 5 uJoules being dumped into a 2 millihenry line in series with the x-ducer?

Beats me..I'm not at the level to measure that.

But, you shoulda seen my condo upgrades...sweet.. Now, restoring an 1873 built house. Test setup is backburner.

Cheers, John

[mtrycraft]

Oh, I forgot, JR can hear the difference....-b

Hell, he can hear the differences insulation causes, at the .00001dB level.

[E-Stat]

Here is a reference where the phase shift and group delay are talked about in wire and where the number I used above came from:

The conclusions of that study using dummy speaker loads are worth considering:

"The fact that the reported observations can be modelled so easily does not, of course, constitute ‘proof’ that no new and unknown cable properties can possibly exist. Nor does it ‘prove’ that cables cannot affect the perceived quality of audio signals."

Indeed.

rw

[jneutron]

The conclusions of that study using dummy speaker loads are worth considering:

"The fact that the reported observations can be modelled so easily does not, of course, constitute ‘proof’ that no new and unknown cable properties can possibly exist. Nor does it ‘prove’ that cables cannot affect the perceived quality of audio signals."

Indeed.

rw

Jim does show he is open with those comments..I'd have been all over him if he said otherwise..course, the word "perceived" within that context is rather interesting..it leaves open the possible explanation of visual cueing as a possible reason.

The fact that the observations can be explained using standard theory just tosses the incorrect explanations out. That was the reason for the analysis.

John

[mtrycraft]

Jim does show he is open with those comments..I'd have been all over him if he said otherwise..course, the word "perceived" within that context is rather interesting..it leaves open the possible explanation of visual cueing as a possible reason.

The fact that the observations can be explained using standard theory just tosses the incorrect explanations out. That was the reason for the analysis.

John

Perceived observations? That is what all the glowing reports of cable differences are based on, perceptions only. And, we know perceptions can be unreliable and fooled so easy.

[Tony_Montana]

"Amplifier-Loudspeaker Interfacing", Greiner, R.A., JAES vol. 28, no. 5 May 80, page 310-315.


RA Greiner discusses the issue of group delay due to skin effects between 100Hz and 10kHz. I would not worry about a 1x 10 to -8 power sec.

Phase angle of 3 degrees at 20kHz if you can hear 20kHz is nothing.

"Effects of cable, Loudspeaker and Amplifier Interactions", Davis, Fred E., JAES, vol. 39, no. 6 Jun 91,

Davis calculated a .04dB loss due to skin effect at 20kHz.

Thank Mtry.

The references you provide seem to be alot of good reading. Do you know how can I get a copy of those reports....free be best ?

You know, I got so bugged down on details about inductance and skin effects of the cable that I forgot to take into consideration the effects of speaker and amplifier on the signal (as others have mentioned). That does bring this issue to whole new light as far as cable's effect on the system [as a whole] is concern.

S I guess the question now becomes...will be worth to fix few nanosecond/dB of signal shift/attenuation caused by cables, as compared to greater magnitude of phase-shift/attenuation caused by speaker/amplifier?

Back to the drawing board again

[mtrycraft]

Thank Mtry.

The references you provide seem to be alot of good reading. Do you know how can I get a copy of those reports....free be best ?

You know, I got so bugged down on details about inductance and skin effects of the cable that I forgot to take into consideration the effects of speaker and amplifier on the signal (as others have mentioned). That does bring this issue to whole new light as far as cable's effect on the system [as a whole] is concern.

S I guess the question now becomes...will be worth to fix few nanosecond/dB of signal shift/attenuation caused by cables, as compared to greater magnitude of phase-shift/attenuation caused by speaker/amplifier?

Back to the drawing board again

Yes, free is best but I don't know. AES is not that expensive, or a nearby University library with EE course?


I would worry about speakers first, today. nothing second, really. Considering the complexity of properly converting the electrical signal to acoustic properly, everything else is insignificant today. Radiation pattern uniformity, enery output uniformity with off axis performances, speaker compression, distortion, etc.

[Tony_Montana]

I live on university campus so I see if I can check out those AES papers. They probably got them on microfilms

[mtrycraft]

I live on university campus so I see if I can check out those AES papers. They probably got them on microfilms

Maybe, but I am not aware that any has been filmed I think they are only $10 for Journal papers.

[skeptic]

The question is not merely one of magnitude of frequency response change but of whether this is the ONLY difference in wires. Linear distortion (frequency response deviation) is easily correctable through pre-equalization to compensate for it. Non linear distortion (harmonic and intermodulation distortion) isn't. If the best the high end cable advocates can come up with is lower linear distortion, they have a very poor case. And so far they haven't even been able to do that. Both forms are easily measurable electrically and their auditory significance can be determined by DBTs. Where are their results? After 25 years I'm still waiting.