Mechanical Isolation Devices: Myth?

[Spirit84]

There are so many products on the market that promise to improve sound quality by placing small vibration absorbing devices under components.
Products like racing cones, sorbothane, springs, etc
Common sense dictates that the following devices would/could benefit from isolating vibration:
Turntables, speakers, tube equipment due to their mechanical nature.
However, what I don't understand is the benefit of using these kind of things under solid state equipment - CD players/transports/DACs, Power amps, etc
Am I wrong about this?

 

[amirm]

No you are not. At the extreme, some electronic devices are microphonic and we can show that they may be sensitive to vibration (multi-layer ceramic capacitors come to mind). Inducing vibration into them requires tons of energy and when you have such energy, it is very much doubtful that you could hear such effects. And at any rate, good equipment design calls for mitigating such things.

All of this said, if you look at the link in my signature on devices to be measured, you see a project where I like to actually quantify the effects of vibrations. Member BE718 does this work professionally and I hope to recruit him for this project. It would be great to put some solid data behind our assumptions here.

 

[astr0b0y]

My favourite 'decoupling' product sold by audio shops are spikes... I mean, really?!
I do have isolation feet on my sub which reduce transmission of vibration through the floor of my living room. This helped those not listening (neighbours, family in other rooms) by reducing their exposure. For me it was a slight negative as it reduced the tactile impact of low bass.

 

[RayDunzl]

I'm unable to detect extraneous vibration at a level that I think would be detrimental to the operation of my stuff.

YMMV.

Whatever I have sits on whatever it came with.

The rack is three shelves of glass on silicone buttons on a steel frame. Nothing fancy.

With a stethoscope, I can hear the hard drive in the cable box ticking and whirring, but can't hear that being transmitted to anything else.

The transformers all went silent after adding an Equitech. That's my only commercial tweaky thing.

 

[Spirit84]

No you are not. At the extreme, some electronic devices are microphonic and we can show that they may be sensitive to vibration (multi-layer ceramic capacitors come to mind). Inducing vibration into them requires tons of energy and when you have such energy, it is very much doubtful that you could hear such effects. And at any rate, good equipment design calls for mitigating such things.

All of this said, if you look at the link in my signature on devices to be measured, you see a project where I like to actually quantify the effects of vibrations. Member BE718 does this work professionally and I hope to recruit him for this project. It would be great to put some solid data behind our assumptions here.

Thanks for the reply Amir - the high-end audio industry is an industry like no other that I can think of. I must confess that over the years I have been a Kool-Aid drinker and wasted a lot of money on cables, etc but no more - I refuse to be fooled anymore. That is why this forum is a G-dsend. Thanks you so much.

 

[Sal1950]

There are so many products on the market that promise to improve sound quality by placing small vibration absorbing devices under components.
Products like racing cones, sorbothane, springs, etc
Common sense dictates that the following devices would/could benefit from isolating vibration:
Turntables, speakers, tube equipment due to their mechanical nature.
However, what I don't understand is the benefit of using these kind of things under solid state equipment - CD players/transports/DACs, Power amps, etc
Am I wrong about this?

Take your knuckle and rap any suspect components. If you hear a thump thru the speakers, it may benefit from some isolation.
Otherwise a waste of money.
Buy some music and preferred intoxicants instead.

 

[amirm]

Thanks for the reply Amir - the high-end audio industry is an industry like no other that I can think of.

As much as we complain and moan , the state of high-end degrades more and more every day! There is nothing, I mean nothing that is useless. Everything removes a veil, reduces noise floor, improves bass, etc. One can sell a Popsicle stick and easily get a number of people who swear it make their system sound better if they stuck it in the middle of the room!

 

[stunta]

Thanks for the reply Amir - the high-end audio industry is an industry like no other that I can think of. I must confess that over the years I have been a Kool-Aid drinker and wasted a lot of money on cables, etc but no more - I refuse to be fooled anymore. That is why this forum is a G-dsend. Thanks you so much.

Yep, same here.

Take your knuckle and rap any suspect components. If you hear a thump thru the speakers, it may benefit from some isolation.
Otherwise a waste of money.
Buy some music and preferred intoxicants instead.

The knuckle-rap test is generally dismissed by the "audiophile" community because apparently the real problem is micro-vibrations! This is why you should hold very still and stop breathing while listening to music - you don't want to disturb any molecules in the room that might degrade the sound quality.

 

[bona998]

And how about this transformers mounted on separate PCB and kind of rubber suspension, how about big capacitors damped with some special paste in many audio equipment and how about these damping parts on digital chips (glued on the upper side) ? Isn't it like some mechanical vibration can be passed on to other parts on the PCB causing mechanical resonance on them or go farther, to the audio path in some kind of harmonics / overtones ? ( we can often see this kind of damping in many high-end stuff like Mark Levinson, Wadia, Arcam, Sony ES etc)

Don't get me wrong - I am not defending this idea, just curious, especially in CD players etc (vibrations inside from transformer and whole mechanics). I can remember in my old arcam alpha 9 cd with dcs ring dac inside (btw do the measurement of DCS DAC! that would be something, but from what I remember they designed their own measuring system, to be able to measure 29,5bit of resolution :>, but at least you should achieve maximum level of the performance for your rack) there was a problem with whinning noise of cd mechanism when playing CDs. There was some kind of vibration from spindle motor or tracking system (focusing). It was so strong that I could hear it in the whole room as a result of mechanical resonance. I remember that it was enough to just glue a bit of damping material on one metal part and it was all gone.

 

[Soniclife]

Thanks for the reply Amir - the high-end audio industry is an industry like no other that I can think of.

I see the same sort of magical thinking in lots of places, quite possibly in all other areas that involve human perception. The beauty industry seems to be full of ever more expensive products with magic ingredients, and the more expensive one always works better. The health industry attracts all sorts of charlatans peddling imaginary solutions, sometimes to imaginary problems.

 

[amirm]

And how about this transformers mounted on separate PCB and kind of rubber suspension, how about big capacitors damped with some special paste in many audio equipment and how about these damping parts on digital chips (glued on the upper side) ?

Large parts like electrolytic capacitors are glued down for reliability during shipping. They are heavy so can sheer off their pins if not secured well. The leads can also break from vibration over time. This is why you see this practice in a lot of electronics unrelated to actual performance or audio.

 

[bona998]

Thanks for clarification Amirm

 

[svart-hvitt]

A somewhat controversial theme, this is.

I wonder, how would you measure to find out if decoupling, anti-vibration devices work or not? As we know, the measured frequency curve may tell us more about the room than about the speaker. So the challenge is to isolate the effect/no-effect of decouplers/vibration devices.

I am curious how @amirm would go ahead and measure this.

 

[amirm]

My thought was simple: build some kind of vibration plate that can resonate easily at a certain frequency. We then measure the audio equipment with the plate running versus not. The resonant frequency of the plate ought to travel into the output of the Audio equipment if there is any issue there.

We can then change that frequency of the vibration plate and see if the measured distortion tracks with it.

This would tell us how sensitive electronics are to highly induced vibrations. If there is no trace of it, then nothing that reduces such vibrations would do any good. But we could deploy some if there are measured effects.

 

[Theo]

What about speaker decoupling devices? Are spikes enough or even good?
If the speakers are well designed, the enclosure vibration should be minimal, especially if the 2 woofers are mounted on opposite sides. So, how important are speaker stands?

 

[RayDunzl]

Are spikes enough or even good?

My mains have adjustable spikes, through the carpet to the concrete slab.

They let me level (or set a rake angle), and provide a solid footing.

I don't think about them past that.

Probably haven't thought about them since 2010 when these speakers were set up here.

 

[restorer-john]

This is why you see this practice in a lot of electronics unrelated to actual performance or audio.

Sony spent a lot of time and money researching this in the 1980s. They damped capacitors specifically for resonance purposes in much of their high end and top ES gear. They designed heatsinks with different length fins that contained resonance stopping castings in the fins and also wrapped the sinks in taught rubber bands to stop heatsinks ringing.

Have you ever driven a high powered amplifier into a dummy load and heard the heatsink reproduce the actual tones you are driving the amplifier with? I hear it all the time. It's caused by the currents in the output devices vibrating and transferring the signal to the heatsinks. Logically, noise and vibration could therefore affect current flows in those same or similar devices couldn't it?

Sony used capacitor clamps, covered in an adhesive velvet, high density foam, and rubber. They made no fuss about it and didn't use it to sell the gear. You only saw it when you dismantled the units or read about their theories. The care in construction makes modern stuff, regardless of price, look cheap and nasty.

On their top CD players of the 90s, specific capacitors are carefully damped, crystals are shock mounted (Onkyo), cabinets are carefully panel-damped and circuit boards are decoupled from key chassis points and/or isolated. Sony used Kyocera fine ceramics feet for their specific properties.

Pioneer TOTL gear did similar things, with their hexagonal (honeycomb) chassis stamping, heatsinking and cast power transformer cases, where the transformers were potted into a die-cast iron case to reduce vibration.

TOTL Marantz gear used beautiful die-cast chassis, plaster filled alloy feet, zinc cast side panels and incredibly sophisticated shock mounting for key parts.

I've got many of these TOTL pieces in my (very large) collection. I've studied their construction, design and sheer engineering prowess over the decades. Quite simply, that stuff is amazing.

 

[svart-hvitt]

My thought was simple: build some kind of vibration plate that can resonate easily at a certain frequency. We then measure the audio equipment with the plate running versus not. The resonant frequency of the plate ought to travel into the output of the Audio equipment if there is any issue there.

We can then change that frequency of the vibration plate and see if the measured distortion tracks with it.

This would tell us how sensitive electronics are to highly induced vibrations. If there is no trace of it, then nothing that reduces such vibrations would do any good. But we could deploy some if there are measured effects.

If you could simulate the tube/metro passing by, or a big guy walking past the (say wooden) floor, it would be nice

Having said that, I believe the pro scene is more interested in speaker decoupling/anti-vibration. Maybe more meat on the speaker bone?

 

[Theo]

My mains have adjustable spikes, through the carpet to the concrete slab.

I don't have a carpet, just wood floor. So no spikes, not good for the floor....

 

[RayDunzl]

If you could simulate the tube/metro passing by, or a big guy walking past the (say wooden) floor, it would be nice.

I had a road trip to UL in Raleigh, to put a couple of racks of Nortel fiber gear on their shaker table, so they could apply various long term vibrations and finally a suite of earthquake waveforms to see what happened.

Something like this: