As a designer of the highest available reference, I would love to shed light on this.
It really depends on equipment as to what is best to hold them in or on, plain and simple. NOT how some other market has confused the public.
Turntables benefit from anti-vibration, anti-magnetic and anti-EMI...
Class A amps benefit from anti-EMI, need a more rigid shelf due to weight, and non-heat-transference materials to control thermal induction to other equipment...
Class A/B amps benefit from anti-EMI...
DVD and CD players benefit from anti-vibration, anti-magnetic and anti-EMI...
Preamps benefit from anti-EMI and anti-ESD... especially with tubes involved...
Cable Boxes / converters with HDD, PVR and DVR's benefit from anti-magnetic, anti-EMI, anti-ESD and non-heat-transference materials to control thermal induction to other equipment...
Tube Amps benefit from anti-EMI... they have moved the tubes outside the Chassis / Faraday Cage for aesthetics.
Speakers benefit from firm coupling, transferring energy to any available surface to help with vibration reproduction. Coupling via spikes can help a subwoofer extend low frequency response by using the floor or subfloor as a massive transducer through coupling...
The combinations are depending on equipment. The difference between racks and stands can be audible, but not with all setups. Since the overall balance rests on the weakest link... usually one problem addresses the combination as a whole.
I have heard hundreds of the most confusing details from my competitor's and consumer's, all the while knowing that none of them take the time to research or examine the setup and basic electronic principles involved.
The audio community is too focused on this or that minute detail whether or not it actually doe anything for the setup.
I do not recommend any shelf treatment other than anti-vibration if no other equipment is directly above, below or to the side. It does no good to shield from nothing.
If you've ever opened a high-end amp, crossover or preamp you notice a massive round torroidial magnet... if you test the magnetic field around it, some have influence over ferrite materials over 30" away... the opinions on "non-marketing" real scientific principles know that flux causes big issues inside some components including DVR, PVR and Turntables or Record Players. Phono pickup needles are metal and can have magnetic or ceramic output
MOST MANUFACTURERS ARE IN IT FOR THE $$ AND HAVE NOT ACTUALLY THOUGHT THINGS OUT.
Manufacturers do not usually use great stands because manufacturers are very, very, very, very cheap. Kind of the opposite of what you would think.
Without naming names :) I have worked with MANY of the world's most luxury manufacturers and it always comes down to "YOU SHOULD GIVE US FREE STANDS SINCE OUR PRIMO PRODUCTS WILL BE ON THEM AT THE (INSERT TRADESHOW)"
Not a bad deal if you manufacture stands that cost a couple hundred bucks... but when you actually have a product that is expensive for a reason, they won't pay a dime. We do not give away $2k+ racks for vanity, and manufacturers of $20k, $30k, $40k, $50k, $60k+++ equipment will not spend $200 on a good looking rack.
When we were first starting out, we were approached by ultra-high-end guys and were shocked that they did not even want to pay 10%!!! AND they wanted to keep the product because it was so cool & advanced!!! It was hard to get going because we had to sell WAY below what it cost us to make just to get feedback in the community.
There are four main high-end racking manufacturers that flat out lie about everything they make and claim
yet they are well known, seriously banking and growing fast. We use real equipment in real setup scenarios to measure our advantages
and they just create spinning fantasy. They sell on emotion
but I am a numbers and reality type of guy
so we do not mix.
A long time ago we just made the resolution that most everyone is crazy and we are quite lucky to have the common sense customers that we do.
I have enjoyed hearing wild claims about how carbon fiber sheets are more dense than three feet of thick granite, how spikes magically remove vibration by generating heat and nameless other marketing ploys to sell product.
Makes it hard when you have the only product that actually does what it claims but doesnt have millions to put a spin on it!
The best quote from a manufacturer is this one: "Our coupling spikes properly de-couple and isolate your equipment"... makes me laugh every time :)
