Question for engineers about enclosure stiffness

No matter how thick you make a panel adding a brace behind it will stiffen it to some degree.

Tappan-braces.gif


dave
 
It just seems the ability of the cone to maintain it's shape under pressure would be overcome by the stiffness of the cab by orders of magnitude. OTOH, I should mention I'm the first to admit I actually don't know what I'm talking about. :blush:
It's probably important to separate the mechanical coupling effect from the airbourne one, I've no idea how you would do that from a measurement point of view, but it might be interesting to compare the difference between a driver coupled and decoupled from the cabinet.
 
So what is the terminology/verb used for stopping the cab walls from vibrating?

Stop. Not going to happen.

Damping causes a reduction in the Q of a “potential” resonance (and given mass is usually added, lowering the frequency).

You will see it touted, but this actually makes for a more audiable resonance (if excited).

Move the resonance up and keep the Q high so that it is VERY unlikely to ever get sufficient energy from the music to excite it.

That often runs against “common knowledge” but has proven to work well in actual implementation.

dave
 
in the sense of was anything able to be measured?

People have tried. Lack of easy access to anechoic chamber where a mic could be useful, leaves us with accelerator sensors. Then an interpretation needs doing.

721Dyna30fig2.jpg


A typical Sterophile wall vibration measurement using artificial input. Here you see a single resonance, high enuff in Q and frequency that it is unlikely to ever get excited. I try to push things even higher.

dave
 
Stop. Not going to happen.

Damping causes a reduction in the Q of a “potential” resonance (and given mass is usually added, lowering the frequency).

You will see it touted, but this actually makes for a more audiable resonance (if excited).

Move the resonance up and keep the Q high so that it is VERY unlikely to ever get sufficient energy from the music to excite it.

That often runs against “common knowledge” but has proven to work well in actual implementation.

dave
I should say "reducing" vibration, not necessarily raising or lowering resonance although I get that one is concurrent with the other. I virtually eliminated bass frequencies from my subs transferring into the floor by simply placing them on 2" thick fired clay patio stones I got from Lowes.



So as per the op, has clay ceramic ever been considered a viable solution? 1/4" thick clay ceramic sandwiched/or lined on the interior? Significant added weight, sure, but still manageable. Think ceramic tiles, but red clay, like bricks.
 
I virtually eliminated bass frequencies from my subs transferring into the floor by simply placing them on 2" thick fired clay patio stones I got from Lowes.

Not because it damps anything. It will have a passband for resomces and being higher than the sub has issues with does not pass them.

If the slab is fairly tightly coupled to the sub you willalos increase the effective reaction mass of the box.

dave
 
Not because it damps anything.
Yes, I understand that. But I'm amazed it works so well but especially that I rarely ever hear about it being utilized. Not patio stones per se, but the fired clay; even on this thread. There's a serious sh**load of high priced accessories for decoupling your speakers from the floor along with endless debates on which is the most effective. But hardly ever any mention of the one that is almost perfect.


I was reading a thread on this topic many years ago on Audiogon where the difference between concrete and fired clay bricks was being discussed. It was made clear concrete is ineffective in stopping transfer into the floor but red clay ceramic would act as you have confirmed.


So as your allusion suggests, it would work well sandwiched between two layers of baltic birch with a suitable adhesive. IYO, what degree of success could be expected? Is there record of this ever being done you know about? Any idea what range resonance would be pushed to using 1/4" thick ceramic?