My take on vibration control is that the ONLY thing that should be moving in an audio system is the driven speaker cones and the air the are designed to push around (allright, also the stylus assembly).
I also suggest it probably most cost effective to locate and fix worse case problems first.
The purpose of any sound control material and its use should be to minimize the acoustic output of anything that is not supposed to have sonic output.
Regarding microphonic output from electronic components, the easy test is to turn the volume up with nothing playing and tap on their covers. If you can hear anything coming from the speakers, that device probably needs help, if not then it is probably not your worst case problem. In general, solid state equipment microphonics will not be worse case problems, although large soft film wound capacitors of the Magic cap ilk can be surprisingly microphonic, as bad as a signal tube in some cases. With tube equipment we try to pick the least microphonic tubes we can find and they usually pass the "tap test". I should note that I have heard no substantial improvement here even trying expensive tube dampers. I suspect they are not working at the resonant frequency of the microphonics.
I am suspect of hard coupling loudspeakers into wood floors with spikes. I wonder if that is just not turning the floor, or shelf, into a large sounding board. It might change the sound, but not necessarily for the better. Hard coupling into a really stiff surface, such as a concrete floor under a thick rug likely is a good idea though.
The loudspeaker is simply a large linear motor used as a vibration generator. Given Newtons' Laws, it makes sense to make the cabinet as massive and inert as practical so that the energy into the motor is used to move air, not move the cabinet. I have heard Magnapans, for example, distinctly improve when the top of the panels was hard braced into the ceiling or back wall. Again, a very heavy padded concrete block on top of big bookshelf speakers made an easily audible sonic improvement when idea was demonstrated to me.
Going back to Newton, it is very hard to take seriously the notion that tiny little expensive "dingleberrys" would have any meaningful effect on room acoustics.
Damping material works by transforming mechanical vibration energy into heat energy. The materials should be as inert as possible to work properly, using the "meatballs don't bounce" theory.
Regarding room acoustics, the goal is to come as close as you can to making the room go away completely within practical reason. The room should be very stiff to support good bass without the surfaces flexing and booming. At higher frequency the room should be acoustically dead. We want to hear the acoustics of the performance and your room was not there when the recording was made. Any reflections from your room surfaces are wrong. Of course we can't completely kill the room, but we can assume that the worse offenders are going to be the surfaces closest to the speakers - - - the walls behind the speakers, and the floor and ceiling close by. Obviously hard reflective surfaces need to be tamed. In my own sound room I turned a horrible sounding suburban "box" into a very nice quiet and useful listening area by the use of thick carpet, acoustic fabric on the walls, and thin Sonex foam panels on the ceiling. Total cost was about $2000. That much spent on better equipment in the original room would have been useless.
Anyway have fun and remember the main rule - - - meatballs don't bounce.
Best regards,
Frank Van Alstine
