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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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In Reply to: spikes and stands - what's the physics? posted by JBC on August 21, 2002 at 16:02:10:
A speaker is trying to reproduce sound waves. The drivers in the speaker need to be perfectly still in order to be able to perform their best. High mass stands do two good things here:1. It reduces movement of the entire speaker.
2. It can damp the floor (except with concrete floors).
Now ideally, you would want a light weight stand, too. Same with a speaker box. But the problem is getting the necessary damping and rigidity. So the easiest way to do it is to increase the weight. There,s more to this, but first about the turntable mount...
A turntable needs to have a rigid, lightweight mount for a simple reason:
High mass stores energy, and most of the energy that a mount sees is in the bass region. This bass energy is not dissipated quickly, which produces a VERY slow, booming sound from the high mass object. Since the turtable is on top of this object, you don't want slow, booming resonances to be near it. So the solution would be to use high rigidity/low mass. This allows the energy to dissipate faster, which means that the stylus isn't picking up the resonances from the mount long after the kick drums hits. This means better bass. Having resonances of the mount being picked up long after the kick drums hits creates slow bass.
As I mentioned earlier, light-weight and super rigid speaker stands would be the best, but since you don't have a sensitive instrument making vibrations into electrical signals near the stands, you can get away with it. Also, as I mentioned above, high mass speaker stands can damp the floors pretty well.
Spikes help to maintain rigidity, but keep a low surface area of contact between objects (duh). What this does is allow each object to resonate more like the object isn't there. The best way to do this is to add some sort of compliant mount between them, but that reduces rigidity. So to keep rigidity to a maximum, and to TRY and decouple the objects, spikes are used. Now, don't get me wrong. Spikes do transmit a good deal of energy. It's like if you have a bowl full of Jell-o... If you just put one finger on the jello, the rest of it can giggle, but if you put your entire hand on it, then the Jell-o doesn't giggle as much. This works in stands because you don't want a low mass mount sitting completely on a high mass mount, and it maintains the high rigidity that you want with the low mass mount. It allows the low mass object to be less tainted by the high mass object that it's sitting on :) But again, this effect isn't nearly as great as with the Jell-o example I gave :)
Spikes are also used to provide a stable base, and adjustable spikes can be adjusted to level the object.
Hope this helps,
Frosty
Frosty Audio - My DIY tweaks
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Follow Ups
- Here's why: - Frosty 13:06:33 08/22/02 (2)
- Re: Here's why: - speyer 20:40:31 08/22/02 (1)
- Re: Here's why: - Frosty 03:30:45 08/23/02 (0)
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