Analysis of speaker cables
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 30th November 2020, 09:40 PM #231 Hans Polak   diyAudio Member   Join Date: Mar 2005 Location: Blaricum Evenharmonics, What is bothering you that results in never ending postings with a strong negative touch. I would welcome a much more positive Evenharmonics. Hans
Evenharmonics
diyAudio Member

Join Date: Apr 2007
Quote:
 Originally Posted by Hans Polak Evenharmonics, What is bothering you that results in never ending postings with a strong negative touch. I would welcome a much more positive Evenharmonics.
Hans, what's bothering you to mock me like that?

BTW, haven't you read my questions to you earlier? I'm sure if you had time to mock me, you would've had time to answer.

syn08
diyAudio Member

Join Date: Aug 2005
Location: Toronto
Quote:
 Originally Posted by jneutron What is being lost in everybody's argument is this: The transmission line impedance at audio is not the concern. It is the RF impedance, but not because of RF. Just energy storage at audio frequencies. The energy that is stored in the cable is stored by inductance and capacitance. The relationship between the two is: LC = 1034 * DC for coax and striplines (field constrained cables), DC being the relative permittivity of the insulation. Or LC= 1034 * EDC for unconstrained cables such as zip, EDC being in the 5 to 10 range based on conductor spacing and geometry. Or LC = 1034 * mu(r) * epsilon (r), (btw, L in nH per foot, C in PF per foot). The energy within a cable is minimum when the inductive storage equals the capacitive storage.. the energy stored in the cable at audio frequencies and DC is absolutely dependent on the load impedance. Starting with equivalence of storage: .5 LI^2 = .5 CV^2 Move C and I^2....get rid of both .5 factors.. L/C =(V^2)/(I^2) Sqr both sides... Sqr(L/C) = V/I...sqr(L/C) is the RF transmission line impedance, V/I is the load impedance. So when a cable has the RF characteristic impedance as the load, the cable energy storage is minimized. Jn

Everything is correct, according to any textbook for EE undergraduates. Only the causality to this topic is violated.

454Casull
diyAudio Member

Join Date: Jan 2004
Quote:
 Originally Posted by jneutron What is being lost in everybody's argument is this: The transmission line impedance at audio is not the concern. It is the RF impedance, but not because of RF. Just energy storage at audio frequencies. The energy that is stored in the cable is stored by inductance and capacitance. The relationship between the two is: LC = 1034 * DC for coax and striplines (field constrained cables), DC being the relative permittivity of the insulation. Or LC= 1034 * EDC for unconstrained cables such as zip, EDC being in the 5 to 10 range based on conductor spacing and geometry. Or LC = 1034 * mu(r) * epsilon (r), (btw, L in nH per foot, C in PF per foot). The energy within a cable is minimum when the inductive storage equals the capacitive storage.. the energy stored in the cable at audio frequencies and DC is absolutely dependent on the load impedance. Starting with equivalence of storage: .5 LI^2 = .5 CV^2 Move C and I^2....get rid of both .5 factors.. L/C =(V^2)/(I^2) Sqr both sides... Sqr(L/C) = V/I...sqr(L/C) is the RF transmission line impedance, V/I is the load impedance. So when a cable has the RF characteristic impedance as the load, the cable energy storage is minimized. Jn
But what does this mean for someone listening to the sound coming from the speakers?

 30th November 2020, 10:28 PM #235 Evenharmonics   diyAudio Member   Join Date: Apr 2007 He's not interested in discussing such thing, as he expressed to me before. Last edited by Evenharmonics; 30th November 2020 at 10:30 PM.
jneutron
diyAudio Member

Join Date: Jan 2004
Location: In fear
Quote:
 Originally Posted by 454Casull But what does this mean for someone listening to the sound coming from the speakers?
Simple. The delay is dependent on the ratio between the cable RF impedance and the driver impedance. Since the driver impedance can swing wildly even with just a sine sweep, the delay will also. If the variation rises to the 2 to 10 uSec swing, it might be audible w/r to imaging. Depends of course on what frequencies, as our imaging ITD sensitivity is very frequency dependent.

As I posted earlier, do the one channel two zip centering test, first with both zips intact then split one. If you do not hear any assymetry, there is nothing to "see", listen to some music and enjoy a beverage.

Jn
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 30th November 2020, 11:28 PM #237 Speedskater   diyAudio Member     Join Date: Sep 2002 Location: Lakewood, Ohio Luckily ITD ( Interaural Time Difference ) is about the lateral movement of a single mid-frequency sound. So no frequency change, no cable delay change. I would think that many crossovers introduce much greater frequency related time differences. * * * * * * * * * * * Also Velocity of Propagation changes a whole lot at audio frequencies in a reasonable cable. 5,000,000 m/s @ 20HZ 125,000,000 m/s @ 20kHz __________________ Kevin Last edited by Speedskater; 30th November 2020 at 11:36 PM.
 30th November 2020, 11:58 PM #238 jneutron   diyAudio Member     Join Date: Jan 2004 Location: In fear The test I mention does not care about the crossover, it first checks that both speakers are identical enough that the image in it's entirety is centered. If splitting one zip changes that, next test. If nothing changes, move along nothing to see here. The beauty of the test is it uses music, and if a motional dependent impedance shift causes a variation in ITD that is audible, this test will see it. Also, it uses a center reference the listener can use to gauge image shift. The frequencies which are not ITD referenced will remain centered, the listener can discern more readily shifts of some content relative to others.. As to prop velocity, that is of no use within the discussion, just a red herring. Jn __________________ I hate all these smart gadgets..I refuse to buy things that are smarter than me. I've made a list of those things... Cabbage just made the list.
454Casull
diyAudio Member

Join Date: Jan 2004
Quote:
 Originally Posted by jneutron Simple. The delay is dependent on the ratio between the cable RF impedance and the driver impedance. Since the driver impedance can swing wildly even with just a sine sweep, the delay will also. If the variation rises to the 2 to 10 uSec swing, it might be audible w/r to imaging. Depends of course on what frequencies, as our imaging ITD sensitivity is very frequency dependent. As I posted earlier, do the one channel two zip centering test, first with both zips intact then split one. If you do not hear any assymetry, there is nothing to "see", listen to some music and enjoy a beverage. Jn
Can you provide a calculation of the delay based on a typical setup?

Also, why do you think a 10 us "delay" would be audible when you have phase wraps with LR4 crossovers that some people can't hear, and sometimes well over 30 ms group delay in the bass region that are generally inaudible?

JMFahey
diyAudio Member

Join Date: Mar 2009
Location: Buenos Aires - Argentina
Quote:
 Originally Posted by davidsrsb The series "R" component is significant at audio frequencies, so the only way to keep to a fixed Z = 8 Ohms impedance is to intentionally raise G by adding parallel resistors along the cable.
Those parallel resistors taking the form of more copper, as in making cable thicker.
No news there.
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