Why Expensive power Cables when Romex behind Wall?

For fun, do a little experiment, buy an inexpensive steel or brass outlet cover and install it in place of your plastic outlet covers. Plug in your system and listen.

You should notice a big change in sound.

WHY?

I will spit this out for discussion.

We cannot cure world hunger & explain every improvement we hear in audio as a direct result of decreasing capacitance and inductance while ensuring a low dielectric absorption. While this is important and the common angle to view how cables effect a system it is but a small piece of the puzzle.

Since everything resonates at certain frequencies, the wire (yes, the stuff inside our walls interconnects, and power cables) will resonate too. This is called (drum roll please...) Mechanical resonance. Mechanical resonance is particularly evident when energy is applied to something. Bang that drum again.... did you hear something?

While inductance and capacitance are very important in cable design and lets not forget dielectric.... Mechanical resonance is to a great degree what we hear when we hear differences in cables (and components). With power applied to the cable, it will resonate and thus emphasize certain frequencies, audibly changing the tonal quality you hear.

Cable geometry, and material used are key in producing neato sounding cables since they can effect the frequencies which resonate and those that don't. Different conductors will all resonate differently. For example: Copper resonates at 26.530MHz, Gold at 1.729MHz, Silver at 4.046MHz, and Platinum at 21.499MHz

The effects of the resonance of the material depends on the gauge of the wire and of course whether or not it is in contact with a sound deadening substance like Teflon - rubber - Shunyata Sand ... Virtual Dynamics Iron Powder or whatever. These substrates weight down the resonance to create the sonic signature.

Make sense?

Okay how about saying it like this:

Power coming into your house is already resonating - when you plug your cool aftermarket power cord into the wall, how do you think this could effect the sound? If the cable changes the existing mechanical resonance, it will change the way your system sounds.

So when you change your electrical outlet cover to a brass or steel cover and plug in your hefty power cord, you will hear a new mechanical resonance in your system and better understand as the topic of this thread reads -- WHY EXPENSIVE CABLES WHEN ROMEX BEHIND WALL... :)

Audioengr. I knew you would reply! That's why I mentioned the steel or brass outlet cover. Its a sure fire way to prove mechanical resonance. Come on man, go get yourself a steel or brass outlet cover - they are cheap 2 or 3 bucks. Replace the cover you currently use with it and then let us know what you hear. Before you write this off as snake-oil you ought to experience what other people are hearing.

Here are quotes from Audioengr's "Technical Papers" - seems he is contradicting himself in claiming that resonance is for the most part not audible - and discounting it as snake-oil here on Audiogon.

Conclusions:
Resonance is a very real behavior in most speaker cables. The nature of the speaker load will vary both the amplitude and frequency of the resonance. The fundamental resonant frequency is primarily a function of the cable length, but
different loads can move this frequency. Resonances can become a problem if high-bandwidth amplifiers are driving high-impedance speaker loads.

Empirical Audio takes resonance seriously, so we design anti-resonant terminations into our cables to eliminate the problem. We believe that the audible "Haze" or "Veils" that often overlay music in high-end systems is in part a result of cable resonance.

What he fails to mention is that there is no such thing as no resonance. Everything resonates. His "Anti-Resonant" terminations just change the frequencies at which the cable resonantes hence making it sound different - Did someone say SNAKE-OIL?

Empirical Audio has taken steps to deal with resonance in our cables. We put anti-resonant terminations in our cables to reduce this effect. To understand the effect of the anti-resonant termination, we first examine a cable without the termination.

Hmmm... so this confirms, you don't remove the resonance (you couldn't anyway) - you just change it. Isn't that what I said in my earlier post? -- Changing the resonant frequencies is one way that different cables sound different.

Thanks Albertporter! Please - don't expect the plates to make an improvement. They will however add a noticable and somewhat annoying brightness to your system. Hopefully this will help folks understand how mechanical resonance can play a significant role in what we hear in our systems.

Also, while you're at it, and if you feel like playing... the tightness of the screws which hold the outlet to the wall make a change as well.

After trying this with several outlet covers I ultimately decided to leave them off all together in my system. Having no outlet cover so far seems better than any other material.

Now if I can just figure out how to firm up that giggly junction box in the wall without tearing my sheetrock to bits.

Audioengr - One thing I have learned in Audio is that measurements aren't necessarily worth the paper they're printed on. What measures good usually - in most cases -doesn't sound good. Measurements don't tell the whole story.

I trust my ears and not fancy-schmancy SPICE simulations.

Here is an Audioengr blooper:

Audioengr wrote:Shielding eliminates susceptability to crosstalk from nearby EM or magnetic fields. It does not help with mechanical resonance.

Duh! Anytime you increase the mass of an object you potentially change the frequencies at which the object resonantes. Adding shielding to a cable will change the mechanical resonance of everything it touches.

Read a thread in Audiogon's Tech Talk Forum Entitled:Tweaks & How My System Disappeared by Jadem6 - a well respected Audiogon member who has been very diligent in tweaking his system.

Most of the changes he's made have been in regard to the Mechanical Resonance of his system. But I am sure that's placebo too right?

Regarding Audioengr's comments on Audiogon vs. what is stated on his website as it pertains to his discounting of the effects of Mechanical Resonance in this thread, Audioengr wrote:

No contradiction. If you take the time to read the paper, you will see that I am talking about ELECTRICAL resonance, not mechanical resonance.

Hmmm.. well given that the second sentence in your "FAQ on resonance" reads:

Resonance can be excited by many phenomena. If you pluck a guitar string or strike a bell, they will ring at their natural resonant frequency and then decay over time due to losses in the systems.

This doesn't imply that you are speaking of electrical resonance. Unless you have an electric bell. So I read further.

ANYHOW get this!! I cut and pasted the text from his Resonance FAQ into a text editor, did a search and find on the text - and bingo! It doesn't even have the word *Electrical* contained in that FAQ. It doesn't say electric, electronic, or even electricity. Whatever Audioengr! What are you hiding?

Audioengr wrote:
As for your metal outlet covers, I beleive that you are experiencing the placebo effect. There is no scientific explanation as to why this should make any difference whatsoever. Resonance requires a high-Q system, which this is not. Even if the outlet cover resonated, what electrical effect could this possibly have?

Guess it depends on what science you subscribe to.
So get this, DUDE!!! there is no electrical effect. This is what I keep saying to you.

When you plug in your power cord and it snugly presses against the metal outlet cover, the mechanical properties of your power cord (and system) change. Maybe you will understand this:

plastic plate + powercord + system = X
metal plate + powercord + system = Y

X sounds different than Y

Nice math huh?

When power flows through the power cord pressed against a plastic cover plate they resonate together. When power flows through the power cord with a metal cover - they resonate together (but differently). The cover plate has an effect on the power-cord and hence the rest of the system.

Plastic is a bit dull sounding and metal is a bright sounding. The thicker the metal the less bright.. wood is odd sounding and not what *I* hoped it would be... the best is to just remove the plate all together.