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Mechanical Isolation Devices: Myth?
- Thread starter Spirit84
- Start date
Hello guys,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.
we are a new company from germany, developing active vibration isolators for industrial applications like microscopy and semiconductor testing. Recently, we were contacted by audiophiles who search for the best way to setup and isolate their devices. Our customer reviews have been highly positive, so indeed it makes an audible difference if you place your equipment on an active vibration isolator.
In order to demonstrate this effect, we have made a video on a turntable placed on our isolator. Since turntables are in fact highly sensitive vibration sensors, all ambient excitation lead to a false signal output (or noise, so to say) that is superimposed to the music itself. Turning the active isolation on reduces the amount of noise to such a low amount, that users speak of a 'revelation of dynamics at extreme whispering volume'.
Our customers have also noticed extrordinary improvements when used with other equipment, see
Seismion - new active isolation platform from Germany
At the end of last year, I was contacted by the founder of a new German manufacturer of isolators called Seismion. The founders are Dr Marcus Neubauer, he has a PhD in mechanical engineering, and Sebastian Mojrzisch, electrical engineer and former manager at Volkswagen (VW) in the...
www.whatsbestforum.com
Looking forward to a fruitful discussion about this topic! IF you have further ideas how to demonstrate the effect of isolation, then let us know.
Greetings, Marcus
TTs make sense. The rest of it... well...Hello guys,
we are a new company from germany, developing active vibration isolators for industrial applications like microscopy and semiconductor testing. Recently, we were contacted by audiophiles who search for the best way to setup and isolate their devices. Our customer reviews have been highly positive, so indeed it makes an audible difference if you place your equipment on an active vibration isolator.
In order to demonstrate this effect, we have made a video on a turntable placed on our isolator. Since turntables are in fact highly sensitive vibration sensors, all ambient excitation lead to a false signal output (or noise, so to say) that is superimposed to the music itself. Turning the active isolation on reduces the amount of noise to such a low amount, that users speak of a 'revelation of dynamics at extreme whispering volume'.
Our customers have also noticed extrordinary improvements when used with other equipment, see
Seismion - new active isolation platform from Germany
At the end of last year, I was contacted by the founder of a new German manufacturer of isolators called Seismion. The founders are Dr Marcus Neubauer, he has a PhD in mechanical engineering, and Sebastian Mojrzisch, electrical engineer and former manager at Volkswagen (VW) in the...
Looking forward to a fruitful discussion about this topic! IF you have further ideas how to demonstrate the effect of isolation, then let us know.
Greetings, Marcus
I glue a carpet sample on the bottom of DIY speakers to get some isolation. Of course, it's OFC (Oxygen Free Carpet).
Absolutely, the advantage for TT seems to be straight forward. Also for tube amplifiers, which are very sensitive to vibrations. Beside that, as mentioned in the beginning of this thread, many electronic components are microphonic. We can confirm that, since we realized it during the development of our isolator aswell. The question is, if this is noticeable. But if we talk about highest quality audio, then it seems to matter for some users.
Do you have any use data to support the audibility of this? Or is it a matter of, people will pay for this regardless of efficacy, so why not take the money?
BTW, you should know that vendors are supposed to contact the mods for a special tag.
Alright, didn't know that. I will contact the mods to change our tag. However, first of all we are here for a technical discussion rather then selling our products. We are also looking to optimize our product specifically to the needs of the customers in audio field, which should be beneficial to the end-user compared to the other products, which as basically the industrial isolators simply used in audiophile field.
@SIY: The question is: What kind of data would you accept to verify the audibility? Actually these are observations made by our customers (see above mentioned thread), not by us. Of course, as a company you need to sell your products, but we definitely prefer to sell to customers which have a real advantage with our product.
Maybe we can together figure out some ways for an objective criterium?
@fpitas: Of course, we can absolutely consider to send you one demo sample for testing. Do you have already some setup in mind, how to use it and test?
@SIY: The question is: What kind of data would you accept to verify the audibility? Actually these are observations made by our customers (see above mentioned thread), not by us. Of course, as a company you need to sell your products, but we definitely prefer to sell to customers which have a real advantage with our product.
Maybe we can together figure out some ways for an objective criterium?
@fpitas: Of course, we can absolutely consider to send you one demo sample for testing. Do you have already some setup in mind, how to use it and test?
No big deal about the tag, but they try to let people here know your biases going in. We have a lot of vendors and manufacturers here. Sometimes we even treat them well
You need to contact Amir about testing, now that I've volunteered him lol. He's the tester-in-chief.
Several possibilities present themselves:
1. Measure the electronic DUT just sitting on the floor or rack or table or whatever with music or test signals playing through loudspeakers. Then remeasure with the device on the platform. Are the differences plausibly above audible thresholds?
2. Capture the output of the DUT under the same conditions as above, then DBT the two captures. Are they distinguishable?
3. Screen the DUT from the listener and move the device on and off the platform randomly (coin flip). Can the listener accurately identify whether the device is on the platform or not? This is a trickier test to perform because of necessary controls, but still possible.
Whilst there are a myriad of things to measure, I would suggest for starters spectral analysis of the output audio signal with the component on a vibration table, with and without the active isolation device. Obviously with long enough captures to see low-frequency vibrations (or lack of) in the output.
Blind testing with the vibration source on and off should work for listening impressions.
Blind testing with the vibration source on and off should work for listening impressions.
Concerning point 1: Would it be the same if we remove the actual music from this equation? When we expect that the actual music signal keeps the same for both measurements, then we can also take the difference of the noise signals only.
This is what we did in the video I linked above. The TT doesn't rotate, the output signal is purely caused by the vibrations from the floor, first without isolation, then with isolation (in this case we even increased the excitation by foot-fall sound.
Here we show the timesignal, which should be easier to understand for the broad audience. But when designing our isolator and testing it, we always take the frequency spectrum into account. What we see then is the (frequncy-dependend) reduction of vibrations, also called 'transmissibility'. This is an exemplary measurement result. Above you see the vibration spectra (floor and on top of the isolator), below you see the ratio (which is the difference of the two above signals in log. scale), how much it is reduced due to isolation. You can see above 10 Hz there is a constant >30 dB reduction. These measurements were done in accordance with ANSI S1.11 2014 standard norm, taking the one-third octave band amplitudes and measured with Wilcoxon 731A sensors.
The question remains - are these vibrations large enough to actually make a noticeable difference in hearing? Here I just want to mention that phenomena like modulation will distort the whole signal. I can imagine the human ear and listening might be rather sensitive to such effects, if trained a bit?
Still, I totally agree: to some (maybe most?) the differences might be too small to make a difference, but generally active isolators are mostly chosen by more demanding persons only, we don't talk about a mass product here.
Then you've eliminated the use case from the testing. It doesn't have to be music playing- it could be an MLS sequence, pink noise, ABC-MRT voices, whatever. The point is that you need a realistic sound field around the DUT to see if the platform has any effect on its performance.
Alright, do I understand correctly that you mean the feedback from music should be included (that means if you play music, then the floor is vibrating stronger than if you are quiet)?
Sure, this influence is not included in above measurements. However, the transmissibility curve (the reduction of amplitudes) will be nearly the same, no matter how the spectrum looks like.
I see, only a test that is monitored or conducted by your tester-in-chief will be approved by this community That's totally fine with us. I will try to contact him and figure out if he would be interested to test our device.
Sure, this influence is not included in above measurements. However, the transmissibility curve (the reduction of amplitudes) will be nearly the same, no matter how the spectrum looks like.
I see, only a test that is monitored or conducted by your tester-in-chief will be approved by this community
That's totally fine with us. I will try to contact him and figure out if he would be interested to test our device.
Amir is solid, but there's several of us who are well-equipped and whose testing is well-accepted here.I see, only a test that is monitored or conducted by your tester-in-chief will be approved by this community
The question is not whether the device isolates but whether that isolation has any effect on the performance of a hifi system's components. Like I said earlier, turntables are a no-brainer, but it gets a lot more dubious from there.
Hi Marcus,
back in the 1970s I worked for Garrard, who made record players, as a noise and vibration research engineer. I noticed then how much environmental vibration record players picked up and found the only way to get a reliable rumble measurement was on an isolation table.
Knowing this, when I eventually, bought a house where this was possible, I set up my system with the record player and electronics in my study with speaker cables going through to the living room.
The trouble is I didn’t like the sound as much and eventually concluded that a lot of what people like about record players is the extra bit of false reverberation they pick up this way and add to the signal.
I have reverted to having the, now little used, record player in the same room as the speakers.
back in the 1970s I worked for Garrard, who made record players, as a noise and vibration research engineer. I noticed then how much environmental vibration record players picked up and found the only way to get a reliable rumble measurement was on an isolation table.
Knowing this, when I eventually, bought a house where this was possible, I set up my system with the record player and electronics in my study with speaker cables going through to the living room.
The trouble is I didn’t like the sound as much and eventually concluded that a lot of what people like about record players is the extra bit of false reverberation they pick up this way and add to the signal.
I have reverted to having the, now little used, record player in the same room as the speakers.
Very interesting. I have often suspected that vinyl is enjoyed for its sonic faults, like groove noise.
