Good tip Piezo, right on! Pbb, here's a thought experiment, that might help understand the possible means by which vibrations can effect the sound of a component.
Firstly, let's consider sound waves, and the energy contained by them. Think about a system running at a "good" listening level, say 90db peaks at 10ft. What does that mean? If your ears are 10' away from the speaker, then some amount of sound energy defined as 90db is hitting your eardrum. Now, just how big is an eardrum? compare that to the surface area of a rectangular box. Then place that rectangular box not 10' away, but between or perhaps right next to one of the speakers. Clearly, the box is receiving many hundreds of times the energy, than the ears are.
Secondly, consider vibrations transmitted from speaker to component through floor, rack, etc. Almost all systems share the same "mechanical ground", and it is usually not a very good one at all - the floor of the listening room - which for most people is a skin of thin layers of wood attached at various points to a lattice of wooden beams. One can imagine that this floor resonates in various manners at various frequencies at various locations.
Clearly, vibrations EXIST. Now, the three more arguable questions: 1) How do the vibrations effect the sound? 2) How can tweaks stop/reduce/change those vibrations? and 3) even if the first two are possible, how could it be audible?
Let's consider how vibrations can effect the sound, in a solid state phono stage for example. A device of this nature is a set of electronic components (transistors, capacitors, etc), SWIMMING in an electro-magnetic field of complex structure. The power supply components, the copper foils conducting current, and the transistors themselves, are bathing each other is em energy. Sure, designers work to reduce the thickness of this soup, but in reality, the "sound" of the phono stage is derived with the effect of this soup already considered. Now comes the imprtant part - MOVE that transistor, within that EM field it is sitting in. High school physics tells us that the very movement will create a current. Thus, if the box is vibrated/resonated in some manner, one can clearly conclude that the electrical signal is being effected to some extent. Next, consider the fact that the vibration is RELATED and caused by the VERY SIGNAL that passed through that transistor some milliseconds ago. The vibration's amplititude and frequency are thus harmonically related to the very signal the transistor is currently trying to pass. Thus, it seems quite clear that "vibrations" can effect the "sound" of a component, and the harmonic relationship may multiply the effect by several factors. So far, we have no conclusion as to whether the "change" is audible or not, but clearly we can conclude that the type of statement "vibrations can not change the sound" is false. Further, I think it is almost impossible to see how these vibrations can FAIL to change the sound.
The physics behind tweaks of this nature are pretty clear. Some of them convert vibrational energy into heat, thereby attenuating the vibration. Others transmit vibrations very effectively, and in theory "remove" vibrations from within a box, and prevent them from "returning" to the box. If a 20lb metal box is well coupled to an 80lb rack, then it will vibrate with less amplitude, and resonate at different frequencies. I can't say much about the removing and preventing return part, but clearly, COUPLING or ISOLATING components will CHANGE the nature of the vibrational problem.
So far then, we have the conclusions that vibrations CAN effect the sound, and that various tweaks CAN change the nature/magnitude of that effect. I would go so far as to change the CAN to WILL.
In terms of actually perceiving the effect, we are back to square zero. I hear it, others don't, and some don't even try, yet proclaim it can't happen. Nothing new there.
Nothing new in this statement by Pbb either: " I find it another thing to assert, based solely on one's personal uncontrolled observations, that HUGE improvements occur for no logical reason. "
The last phrase is clearly false, yet it is thrown around like some ultimate postulate of the universe. The logical reasons clearly exist, and even if we are not currently aware of them, that does not mean they do not exist. (the reasons, not the sounds or perceptions).
"huge" is clearly a relative term. If one has never gotten to know "excellent" wine (like me), the difference between two bottles of similar wines would escape me, let alone the difference after one glass has sat on the table for a few minutes. Yet, a wine connissuer would go on and on about the "huge" differences between those same two bottles of wine, and how one of them needs to decant a little longer. After a little learning and some experience, I would also notice at least some of those differences in the boquet and the body of those wines.
What is getting REALLY old and boring is the attitude "ho hum, you fools are enjoying your circle of mutual masturbation, and who am I to stop your fun. But here I am anyway, with this pamphlet I have about blindness."
