Theoretical cable question

Kimber gives you the inductance per unit length on their cables, and is a long-time manf. with a good track record.

I have never seen any basis for the claims on silver cable.

You will have to try a number of cables to find one you prefer, hence the cable 'rental' firms.

1-3 ft is not likely to cause much difference and you are smart to keep it short (another adv. to mono-block amps)

Thanks for your thoughts. 

I run my ESL's exactly the same way: 50 cm cables from mono blocks.

Based on my experience, I suspect that over such a short distance any differences are purely theoretical and inaudible. 

That said, Litz wire (many small, independently insulated strands) gives better high frequency response. In theory.

Also, according to the Maxwell Equations, capacitance attenuates high frequencies at line levels, while inductance is the problem at power levels. That means two ribbons in very close proximity to maximize capacitance and minimize inductance. Goertz speaker cable is a good exemplar.

But I don't think you'll hear any difference at all. Good luck!

Thanks. I'll try and see if I hear a difference. 

To elaborate on some of the comments that have been made (and in some cases to contradict them):

1) For a given cable type, inductance, capacitance, and resistance are directly proportional to length.

2) The impedance presented by an inductance is directly proportional to frequency, and in the case of a cable presents itself in series, rather than in parallel. Consequently, the impedance presented by the inductance of a length of speaker cable that would be used in a home will be negligible at bass frequencies, but as Terry9 alluded to it may have some significance in the upper treble region. Especially if the cable is long and the speaker has low impedance at high frequencies, as do many electrostatics in particular. What is important is the relation between the impedance of the cable and the impedance of the speaker, at all frequencies that may be significant.

Specifically, the impedance presented by an inductance (referred to as inductive reactance, denoted as XL, and measured in ohms), is defined by the following equation, where f is frequency in Hz and L is inductance in Henries:

XL = 2 x pi x f x L

("pi" = 3.14, approximately).

3) The impedance presented by a capacitance is inversely proportional to frequency, and in the case of a cable presents itself in parallel (i.e., between + and -), rather than in series.

Specifically, the impedance presented by a capacitance (referred to as capacitive reactance, denoted as XC, and measured in ohms), is defined by the following equation, where f is frequency in Hz and C is capacitance in Farads.

(Cable capacitance is often indicated in units of "pf" per foot or per meter. 1 pf = 1 picofarad = one trillionth of a Farad):

XC = 1/(2 x pi x f x C)

Under most circumstances involving analog audio signals the effects of cable capacitance, if any, result mainly from the low pass filter that is formed by its interaction with the output impedance of the component providing the signal. The output impedance of a power amplifier is low enough to make that a non-issue in a speaker cable of reasonable length. But as Terry9 correctly indicated it may be significant in some cases for line-level interconnects, if the output impedance of the component providing the signal is high at high frequencies and/or if the cable is long.

However in some cases the stability of a power amplifier or the power stage of an integrated amplifier may be marginal when it is subjected to a particularly heavy capacitive load. Especially in some cases involving amplifiers that have low effective output impedance (as do almost all solid state amps), and that use significant amounts of feedback. So if the speaker cable being used has particularly high capacitance, such as Goertz (which achieves ultra-low inductance at the expense of ultra-high capacitance) the result may be such things as "overshoot," ringing, phase response anomalies, or even destructive oscillations. Goertz, however, provides what are called Zobel networks which can be used with their cables to minimize or eliminate such possibilities.

It should be kept in mind, though, that small amounts of overshoot, ringing, phase response anomalies, and other such inaccuracies could conceivably be interpreted by some users with some systems as supposedly desirable attributes, such as "sparkle" or "air."

4) All of that being said, I don’t think that the differences a one to three foot length of speaker cable might make in a given application, if any, can be predicted based on theoretical considerations. And I would also expect any such differences that may be reported to not have a great deal of consistency among different systems, in part because of the dependencies on speaker impedance and amplifier design that I cited above.

Regards,
-- Al