Do materials alter frequencies and speed?

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

Perhaps this one of the reasons the 10 guage Zip Cord exhibits lower Capacitance and Inductance than many of the more expensive speaker cables in the chart referenced above and why none of the more expensive cables produce a more linear frequency response over the audio band.

Rsbeck: We've been through this before. The test results published for frequency response do not take into account impedance variations whatsoever.

As i've posted before based on figures extrapolated from the data that they provided, "zip cord" can introduce very measurable treble roll-off starting within the upper midrange / lower treble region on some speakers. Your refusal to see or acknowledge this potential problem, yet quote the same crap over and over again, makes me question your agenda.

The fact that you keep promoting zip cord yet chose other wires to run in your own system speaks volumes in itself. Make us proud and put your money where your mouth is. Doing so and selling your "fancy cabling" will buy you another couple of discs and tell us that you really do believe what you post. Saying one thing and doing something completely different doesn't set much of an example, nor will it sway anybody to believe what you are promoting. Once you swap those cables out of your system, you can keep telling yourself that it sounds exactly the same and that you are happy with your decision. Sean
>

Sean -- sorry, buddy, but you know I don't care about your "roll-
off" that happens outside the range of audibility so it doesn't matter
how many times you bring it up, it ain't like fine wine and it doesn't get any
better with age.

In fact, it is the exact kind of half-truth I am talking about.

I challenge you to present the facts honestly and do not leave anything out.
Every time you talk about this "roll-off," I challenge you to post
the truth -- that it is outside the range of audibility. I think that is a pretty
important point.

I posted a reference to a whole chart of cables I do not own, but I am not
allowed to mention the Zip Cord listing? Not allowed to say anything good
about Zip Cord? Who made that rule? You?

Finally, next time, don't just reference what YOU wrote last time -- try to
recall what *I* tell you each time you bring up the bogus "roll-off" -- that
way, you can expect me to have the same answer as before.

Save us both time.

Rsbeck - you can see plots of measured and computer simulated response of ZIP cord versus my speaker cables at this website:
http://www.empiricalaudio.com/frclarity7_electrical_performance.html

The simulated and measured are both obviously rolling-off with ZIP and have different phase response. The only issue is whether this is audible or not, and based on my listening tests, it is. My cables must be doing something right as they were favorably reviewed in April Sterophile, and I might add that I have never put any ads in Stereophile.

Steve N.
Empirical Audio
Manufacturer