Do materials alter frequencies and speed?

My impression is that people like to throw myths and wive's tales together
with things that are half-true and extrapolate from that into the land of the
hypothetical based on hypothetical on top of wishful thinking.

I had a strong feeling that no one was going to be able to tell me anything
solid about this affect on dynamics, how it is measured, or if there is anything
to back any of this.

What isn't in dispute in this discussion is that it is desirable to have low
capacitance and inductance. But, we also know that several very expensive
cables exhibit far higher inductance and capacitance than 10 guage Zip Cord
(See table referenced above). If there *was* any solid proof that higher
capacitance and inductance -- at the levels exhibited by these expensive
cables -- degrade the performance of these cables with regard to dynamics
-- that would be interesting. Especially, perhaps, to the owners of those
cables. But, since there apparently isn't anything solid, "No one
knows for sure -- there are a lot of variables." We don't really have
anything.

Yes, we do know that the configuration matters most if one is attempting to
manipulate inductance and capacitance, but this just supports the counter-
point that materials -- silver versus copper -- matters least. And that's the
answer to the original question. If capacitance, resistance, and inductance
matter most with regard to dynamics, a whole lot of expensive speaker cables
do not measure as well as 10 guage Zip Cord (see table referenced above) nor
do they provide more linear frequency response (see frequency response
charts included in referenced article).

Thank you Bob. Coming from an EE with an open mind and years of audio experience, your summary was both brief and technically excellent ( as usual ). I couldn't have said it any better and i surely couldn't have done it as briefly as you did. Kudo's to you for an excellent post : ) Sean
>

Frequencies and speed is not accurate to describe the effect. Geometries aside (spacings and wire gauge etc) , materials in cables have several effects, both insulation and metals. Lets start with metals:

The crystal lattice in the metal can cause reflections in the cable, because they are impedance discontinuities. These occur at very high frequencies, but this does not mean that they will not become audible. Depends on whether the driver reacts to these reflections or not. most of the time, this is audible and sounds like sibilance on top of the high-frequency information in the music. Metal purity, choice of metals, cryo treatment and other factors affect this.

The insulation has several effects as well. Besides the obvious effect on capacitance per unit length, the dielectric material absorbs charge and releases it when transients occur. Depending on the material, it is not completely released either. In general, if the time-constant of the material release is slower than the time-constant of the transient, smearing will occur. Dielectrics with a lot of air will usually have the least dielectric absorption effect. The effect of this is usually a loss of HF dynamics, often described as a roll-off, but technically it isn't.

>>most of the time, this is audible and sounds like sibilance on top of the high-frequency information in the music. Metal purity, choice of metals, cryo treatment and other factors affect this.<<

This is what I mean by myths and wive's tales. I predict no hard evidence will be offered to back the idea that any of this is true.

>>the dielectric material absorbs charge and releases it when transients occur.<<

Sounds like advertising from a cable site -- this has been debunked.

>>smearing will occur.<<

No one has ever been able to measure audible distortion caused by a speaker cable. No one. Zip, zilch, null set.

>>The effect of this is usually a loss of HF dynamics, often described as a roll-off, but technically it isn't.<<

This ought to be measurable. I predict we will not get any back-up for this, either. No way to quantify the loss of dynamics, no double blind listening tests to see if anyone can hear any such thing.

Basically, in the audio world, you can say anything you want about cables because standard of proof is completely absent. So people run around saying whatever they want, throw a few big words in there for good effect, people repeat it and pretty soon, you've got another urban audio myth -- and possibly another cable sale.

From Audioholics Web-site ----

Dielectric Absorption in Cables Debunked

Before we debate the relevancy of Dielectric Absorption relating to speaker cables, and commonly perpetuated by many exotic cable vendors and cable cult hobbyists, let us first define the roll of a dielectric.

According to Wikipedia (http://en.wikipedia.org/wiki/Dielectric) the definition a Dielectric material is an insulator. The ideal dielectric would be a vacuum or infinite impedance. However, real world dielectrics do NOT have infinite impedance and therefore are not perfect. As frequency increases, the Dielectric starts exhibiting shunt resistive losses which can be measured and quantified as signal loss across the termination load. Fortunately for our application (audio) these shunt losses don't begin to surface until frequencies much higher than the audio bandwidth.

At audio frequencies, even the worst dielectrics (IE. Polyvinyl Chloride, aka. PVC / plastic) used in cheap and many exotic speaker cables maintain shunt resistive impedances in the mega ohms or more. When dealing with a low termination impedance of a loudspeakers (usually in the order of several ohms) the dielectric shunt resistance is on the order of 10^6 greater, thus the parallel impedance remains virtually unaffected and we see no losses due to the dielectric at audio frequencies.

Cont'd....

http://www.audioholics.com/techtips/audioprinciples/interconnects/dielectricabsorptioncables.php