[Uncle Erik]

Take the advice of someone selling something as the words of a salesman. You really don't expect them to raise critical questions about what they're selling, do you?

What's interesting about vibration "control" devices is that there are contradictory products on the market.

Some are very rigid and some are very soft.

Yet - for whatever reason - all of them are claimed to work.

How can that be? They work on opposite principles. Assuming one of them works, then the opposing design must not work. It is not possible for both to work. Though it is possible that both of them are snakeoil.

Also, just how much vibration is harmful? What is there isn't significant vibration to begin with? Would you then have a solution in search of a problem?

Here's something I tried once: I do a bit of woodwork and have some fine finish sanders. A favorite is a very nice Porter Cable that is excellent for fine trim and furniture work. I took the sanding pad off and put it on the bottom shelf of the stereo rack and turned it on. The rack was, unquestionably, vibrating. I then listened to a few songs on the DT48, with the Zana and some SACDs. Both the amp and SACD player were on the vibrating rack.

There was no difference. Both sounded the same, vibration or not, with just the stock feet.

Now, the turntable was not happy at all with the vibration. I couldn't bring myself to lower the needle. I'm sure that sound would have been terrible.

Still, no effect on the amp or SACD player.

Anyone with a sander - or other vibrating device

- should try this out.

 

[b0dhi]

The only thing I can imagine is that the crystal oscillator, being piezoelectric, has more jitter when there's vibration. However this assumes that small amounts of jitter are audible and that the footers actually have any effect at all in reducing vibration.

 

[Eric_C]

Uncle Erik: that's a really strong line of logic running thru your argument. Could you provide specific examples of soft resonators/footers, since some folks have kindly offered links to hard material devices?

 

[Steve Eddy]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Anyone with a sander - or other vibrating device - should try this out.

I'd love to.

But where can I find a sander that's silent?

se

 

[Armaegis]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Anyone with a sander - or other vibrating device - should try this out.

Well *that* will make for interesting conversation when the wife comes home...

 

[terriblepaulz]

Quote:

Originally Posted by BIG POPPA /img/forum/go_quote.gif Look at websites like Brass Footers-Mapleshade to learn about footers. I use the brass footers and Isoblocks and like them very much. Here is some info on resonators Acoustic Art - Synergistic Research. If you spend several thousand on a speaker system you will learn all about them. With headphones, resonators are not a concern to me.

When friends and family ask me for an example of silly things purchased by audiophiles, I point them to the Acoustic Art site. It's telling that the same enterprise entered into a joint venture with Mikhail of Single Power fame (or is it infamy?):
The Enigma Story - Synergistic Research

 

[jax]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Take the advice of someone selling something as the words of a salesman. You really don't expect them to raise critical questions about what they're selling, do you? What's interesting about vibration "control" devices is that there are contradictory products on the market. Some are very rigid and some are very soft. Yet - for whatever reason - all of them are claimed to work. How can that be? They work on opposite principles. Assuming one of them works, then the opposing design must not work. It is not possible for both to work. Though it is possible that both of them are snakeoil. Also, just how much vibration is harmful? What is there isn't significant vibration to begin with? Would you then have a solution in search of a problem? Here's something I tried once: I do a bit of woodwork and have some fine finish sanders. A favorite is a very nice Porter Cable that is excellent for fine trim and furniture work. I took the sanding pad off and put it on the bottom shelf of the stereo rack and turned it on. The rack was, unquestionably, vibrating. I then listened to a few songs on the DT48, with the Zana and some SACDs. Both the amp and SACD player were on the vibrating rack. There was no difference. Both sounded the same, vibration or not, with just the stock feet. Now, the turntable was not happy at all with the vibration. I couldn't bring myself to lower the needle. I'm sure that sound would have been terrible. Still, no effect on the amp or SACD player. Anyone with a sander - or other vibrating device - should try this out.

I would speculate that the differences I can hear in replacing the support of my source components that I described certainly could not be discerned by me over the noise of a finish sander..even if the sander were in the next room. The differences were in clarity, detail and soundstage...everything occurred to be in a sharper image...more clearly defined in space. Not a chance I could hear that kind of thing over a finish sander. I use Bosch sanders and perhaps their louder than your PC.

Here's an experiment you could try, though I'd leave your sander in the wood shop for this. Using a tuning fork would be ideal and much safer. With no music playing and the system on and volume moderate to low, take the tuning fork, tap it so it's resonating and hold it nearby, but not touching, your preamp tubes (assuming you have tubes in your pre-stage). If you insist on using a finish sander you're on your own. See what, if anything, you might hear. Just a thought.

 

[TheAttorney]

Quote:

Originally Posted by Eric_C /img/forum/go_quote.gif Uncle Erik: that's a really strong line of logic running thru your argument. Could you provide specific examples of soft resonators/footers, since some folks have kindly offered links to hard material devices?

HRS Nimbus is an example of soft footers (and top plates):

audio industry noise reduction technology

These are soft(ish) polymer material and metal sandwiches. They, allegedly, absorb the vibrations without storing-and-reflecting back. The bigger the area covered the better. This differs from pointy hard footers which, allegedly, drain away the vibration into the underlying platform. The smaller the point the better.

It is perfectly plausible that a problem can be sorted by different solutions, in this case, absorption or draining, but I don't have enough experiece on these matters to judge which is best.

The HRS stuff has the usual high end tweak unbelievable prices. So do try before you buy.

 

[penguin121]

Quote:

Originally Posted by TheAttorney /img/forum/go_quote.gif These are soft(ish) polymer material and metal sandwiches. They, allegedly, absorb the vibrations without storing-and-reflecting back. The bigger the area covered the better. This differs from pointy hard footers which, allegedly, drain away the vibration into the underlying platform. The smaller the point the better.

Aside from possibly with turntables, I seriously doubt that household vibration levels have any impact on component performance. However, that doesn't mean that the mounting feet in question won't reduce vibration level equipment, just that doing so is likely a waste of time and money. With that said, here is how each type of mounting feet would function, assuming that they are properly designed.

If properly designed (sized correctly and use a high loss factor material), the soft mounting feet should be good at isolating the equipment from environmental vibration over a broad frequency range. Basically the feet act as a spring-damper system, so above the fundamental mount resonance the feet will provide a sizable reduction in transmitted vibration. Near the mount resonance, vibration transmitted through the feet will actually be amplified, but assuming that the mounting feet are selected so that the mount resonance is a a low enough frequency, this does matter too much. The mount resonance will depend on mount material, mount size, number of mounts and the weight of the supported gear. Soft mounting feet won't do anything for vibration generated by the mounted component, well unless you count isolating your stand from those vibrations that is.

Hard mounting feet on the other hand won't do anything to reduce vibration through the feet to the equipment. If the feet are heavy enough, they will add mass to the low frequency global vibration modes of the component, providing some reduction in vibration levels generated by the component. However, at higher frequency where local vibration modes dominate, the feet won't help, as they don't contribute mass to those vibration modes. In fact, at higher frequencies feet of any type don't really matter at all for vibration generated on the component. The only ways to reduce these vibrations would be reducing the source level (i.e. better motor on the cd drive) or locally applied damping. Note that the use of high versus low frequency in this discussion is relative the structural vibration characteristics of the component, not the audible frequency range.

 

[project86]

How about a simple test with a portable CD player? Disable any anti-skip function that it might have. Plug in some highly resolving headphones, preferably with a long cable. Close your eyes. Have an assistant hold and randomly shake the CD player, just a bit but not enough to make the music skip. Take care that you can't feel the shaking through the headphone cable (hence the longer cable). Raise a hand to indicate when you think he is shaking the player. See how often you can tell. If the issue is big enough to require footers and the like for stationary gear, this torture test should be easily passed.