After reading your article on boomy bass, I find your experience hard to relate to what I know in theory.
By mechanically grounding the speaker box resonances, aren't you causing the "resonance conductor" (in your case the wooden panels) to vibrate as well? Also, the floor will also start to vibrate. Won't all these contribute to worse sound?
Regards Lip Wee
7th May 2000
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Hello Lip Wee, A few points to note before I go into details in my answer.
1)By your own admission your knowledge on this subject is based on theory. 2)You speak of vibrations as though it was a pest- that is something that should be eliminated in a sound system and allowing only the vibrations to come from the drivers.
Theories are based on experience and observations. If an observation of a natural occurrence produces a result that is in conflict with an accepted theory, which would you throw out - the observation or the theory. I think the answer to that would be obvious.
A thorough scientific method to ascertain the "truth" of an observation would be to see whether it is consistently repeatable. This I have done so by applying the idea to my own music system and also to the system of my friends and customers. The effects on the sound was consistent, though the acceptance of these results as an improvement was not as consistent. Applying the mechanical ground to a system consistently produce a sound that was cleaner in the bass though other benefits were also observed. But in certain systems, the users may feel better off without it. I can see this happening in systems in which the sound is already too clean meaning that the sound is dry and taut with minimal decay and bloom. This is because applying the mechanical ground actually reduces allot of the speaker's box resonance that color the sound. However it is not a good idea to eliminate this as this can create a very dry and mechanical sound.
Your worry was that applying the mechanical ground would create more vibrations in the floor, the wall etc.. that would make the sound worse. There are a couple of things wrong with this view. First is that this method of tuning your system do not create vibrations. The energy that cause these vibrations came only from the speaker's drivers - primarily the woofer which of course derive its power from the amplifier. This energy if not drawn out by the mechanical ground would remain in the speaker's cabinet causing it to vibrate even more. This is what make the speaker sound boxy especially if this energy causes the speaker's cabinet to vibrate with such intensity that it produces overtones that are not part of the natural harmonics of the music. This brings me to the next point which is that even if your whole room is vibrating in sympathy with your speakers- you will not hear the room. You may hear some buzzing or rattling if you play your music loud enough to create these extraneous noise that is not part of the harmonics of the music. From my own experience I find that if you can energize your whole music room in this manner ( without the buzzing) the music production is more lifelike and involving. This is very similar to attending a live concert in a good concert hall. Natural reverberation is controlled not only in terms of how much but also in terms of from which directions. Too little reverb results in a dead sound, too much and everything becomes ill-defined and muddy. Though natural reverberation is not exactly the same as energizing a music room, the effect on the musical experience can be very similar.
Taking this from another angle to explain the workings of the mechanical ground. Consider speakers stands. Most audio buffs know the importance of these to the performance of their bookshelf speakers but not many of them will be able to explain why some stands sound better than others or why certain stands work with certain speakers and not others. Or why putting hard cones between the speaker's base and the stand make it work better and sometimes its better to use blu-tack or rubber for this purpose. You will often get inconclusive answers or worse that it is all a black art. Actually an understanding of the mechanical ground clarifies many points related to this topic. It has all got to do with how well the stand draws away vibrations from the speaker that it is supporting. If it is heavy and rigid it will be able to do this more effectively. However you can effectively nullify this by putting something soft in between the speaker's base and the stand. You can use blu-tack or rubber feet. These impede the vibrations from the speaker from going to ground. The result is a stronger or boomy bass because of stronger vibrations in the box. Thus a stand that provides a better mechanical ground gives better definition in the bass and better clarity all round. But if your system sounds lean and lightweight, you may want to put blu-tack beneath the speaker to give added bloom and weight. There's no right or wrong , its what you like and you are listening to your system , not your friends. The mechanical ground idea gives the audio buff an additional weapon in his arsenal of audio tweaks however it is imperative to have a good understanding of it and how to use it selectively. This is true with all tweaks.
Think of vibrations as a friend that needs understanding, not as an enemy that must be eliminated. After all without vibrations there would be no music.