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How do you deal with vibration?

Greetings all,

Many of us work very hard to keep vibration out of our equipment. I was hoping we could share our experiences with each other. I was wondering what other DIY methods people are using?

I personally have had good luck with shipping open cell foam under plywood. I find that about 60-70 percent compression works best. I place the foam underneath some plywood (Using spruce 3/4 inch). Then I place the component on the plywood. However, I think this more isolates the component from outside vibration. I don't think it does much to drain internal vibrations, especially in a CD transport.

Also I can not find open cell foam in town any more. I am ashamed to say that I actually went to Wal-mart to buy some. Now they don't carry it any more. So I was wondering where else I can get some?

I am currently thinking about building a Sandbox for my CD player and amp. Then putting the sand box on top of some sort of isolation material (open cell foam or cork rubber etc.) My thoughts are the foam or cork or etc should help keep the vibrations from getting into the equipment and the box should drain the internal vibrations.

Also, what are peoples experience with different woods. I live in BC so I can get most wood fairly cheap. I imagine every wood has it's own sonic signature due to it's resonant frequency. What works best? Solid maple, birch ply, MDF, walnut, mahogany etc...?\

Anyways, feel free to through ideas and experience (both good and bad) out there. It would be good to know what works and what doesn't.

Happy tweaking,
Nick
nickway

Showing 9 responses by eldartford

eldartford
4,262 posts
 
Tbg is correct that a wire moved in a magnetic field generates a voltage. But there is no reason to believe that the stray magnetic field is large enough or the vibration-induced movement great enough to have any measurable or audible effect.

The purpose of comments discounting the effect of vibration (except for TT and tubes) is not to debase anyone's belief. We don't care what Tbg believes...whatever makes him happy. The purpose is to forewarn newcomers who might think his opinion is accepted truth.
eldartford
4,262 posts
 
He said..He said. How do we know the truth?. Well, why not make some measurements.

I put my PS Audio PS II outboard phono preamp (a high gain circuit that would most likely be affected by vibration) into a plastic hamper with a small speaker system and my calibrated SPL mic. I powered the speaker with a spare preamp and amp. For a signal (vibration creator)I fed in a 125 Hz warble tone. The two Behringer DEQ2496 (of my regular system) allow me to measure SPL (inside the box) and, simultaneously, the line out signal derived from the phono input coming from the outboard PS Audio preamp. Ideally this signal would be zero with no LP playing. The idea is to see how much signal can be generated by shaking the hell out of the phono preamp circuit.

Using the auxillary preamp, I cranked up the volume to 110 dB inside the box. Then I turned the warble tone OFF and ON, and observed the line out signal to be -77 dB rms in either case. In other words, the 110 dB SPL from a loudspeaker 3 inches from the circuit had absolutely no effect.

Then, to be sure that I was not making observations at too low a main system volume setting, I turned off the warble tone, relocated the mic to the listening room, and played a LP with the same volume setting (maximum)on my main preamp. The LP SPL for a moderately loud passage was 90 to 100 dB rms.

From this test I think I know the effect of vibration on an electronic circuit. What do you think? And why.
.
eldartford
4,262 posts
 
Newbee...IF any sensitivity were detected, THEN a sweep of frequencies would pinpoint the frequency of greatest sensitivity. However, at least for my equipment there is no sensitivity.

Theaudiotweak...Your basic assumption doesn't make sense to me. Vibration will REDUCE friction in a mechanical system (the opposite of what you suggest) but I can see no reason to think that electronics would draw more current when exposed to vibration.
eldartford
4,262 posts
 
Tbg...I just reported some facts, and everyone can draw their own conclusions. But I must point out that in dealing with 110 dB sound/vibration input, subtle resolution is a bit of a joke.
eldartford
4,262 posts
 
Tbg...I completely agree that turntables and tube amplifiers need all the vibration control they can get. I was very skeptical about SS circuitry, and the simple test I performed showed that, at least for my phono preamp, vibration has no effect.

CD players are still an open issue in my mind. However, I have figured out a way to test mine. I have a CD test disc which includes two tracks, digital zero (which should be zero signal) and one LSB (which is electrically measurable but inaudible). I can put the player in the test box, play these tracks, and see if the player output is affected.
eldartford
4,262 posts
 
Jadem6...No offense. And well-written comments. I drive a Honda CRV instead of an Acura, because it does everything I need and leaves me with enough money to fly my airplane. Same deal with audio. I could afford the most expensive gear (well almost) but I could never justify it.

This thread is about a general technical issue, vibration, and its possible effect on equipment, which would logically affect all levels of audio equipment. If anything, cheap stuff, with no designed-in vibration control would be most sensitive.

I know that vibration control is very important for LP turntables, and for tube amps. Some people have suggested that electronics are also affected, an idea that seems unlikely to me. However, rather than talk back and forth and work ourselves into a fit about this I prefer to simply make some measurements and find out what is really going on. There are many audio characteristics, like "soundstage", "transparency", "imaging", that I cannot measure and neither can anyone else. But some things, like sensitivity to vibration are easy to measure, so why not do it. If my findings do not please you feel free to make your own measurements.
eldartford
4,262 posts
 
OK. I did my DVD player, a Denon 2900 with Underwood mod.

As before, I appled a 125 Hz warble tone at 110dB measured by the mic resting on top of the player.

I used the Denon HI-FI Check CD, track 37 (digital zero) and track 38 (one LSB square wave). The player rms output was around -77dB and -76dB respectively regardless of whether the vibration input was ON or OFF. I paid careful attention to the peak reading (displayed numerically about once a second) because one might expect any effect to be of the nature of a digital data error. All peak data was consistent with the variations of the rms value.

Them is the facts. Make of it what you will.
eldartford
4,262 posts
 
Tbg...Noone is trying to convince you of anything. I am trying to decide what I need to do, and, just as you report the results of your listening tests, I will report my results. Other guys might benefit from my experience as well as yours. Would you like me to test my turntable, so that I can show the kind of results you like? That would be a waste of time because I already know the importance of vibe control for turntables.

Peace.
eldartford
4,262 posts
 
I thought this thread was about vibration. Please don't extrapolate my views into other aspects of audio where they don't apply, and then criticize me for these views.

To reiterate..."There are many audio characteristics, like "soundstage", "transparency", "imaging", that I cannot measure and neither can anyone else. But some things, like sensitivity to vibration are easy to measure, so why not do it".
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