charleski
Major Contributor
The only proper data I've seen is an old study by Mullard: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?
The only proper data I've seen is an old study by Mullard: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?
I agree, from a common sense viewpoint. Still, if someone can show actual data that isolation makes a difference, I'm interested.Mechanical Isolation can be important for:
a] Turntable, tonearm, cartridge combinations.
b] some vacuum tube components.
c] hand held microphone and musical instrument cables.
d] units with some boutique capacitors.
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Loudspeaker are a different topic!
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no well designed modern electronic unit needs Mechanical Isolation.
Probably very similar for most tube based electronics.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.
The cap's can be microphonic?d] units with some boutique capacitors.
I'd love to.Yup, just try slapping a big HV Deluded (sic) DC biased capacitor, and watch the scope trails jiggle
Well, if that's the case, we won't see any effect. But if the sound field gets transmitted mechanically to the DUT, or if vibration is present in the environment from A/C or passing traffic, then if it's microphonic, we may see some changes. And then, if not, we have good evidence that the effect of the device for audio systems is psychological rather than physical.But the isolation table stuff does little to eliminate contamination from air-born vibrations beating on the microphonic device
The cap's can be microphonic?
Don't remember reading that before.
Thanks, but what about the mass produced parts like you used.@Sal1950 Boutique caps are often wound poorly with insufficient tension (especially PTFE), and that can make them microphonic. This is why I will only use mass produced machine made caps in my builds.
Much lower levels. You'll see almost nothing in a tap test under normal use conditions. The same can't be said for PTFE boutique "hand made" caps, which may as well be microphones.Thanks, but what about the mass produced parts like you used.
Do the offer just lower levels or are they basically inert?
If I taped them with my finger can the result be seen on a scope?
Just curious
TIA
Many thanks.Much lower levels. You'll see almost nothing in a tap test under normal use conditions. The same can't be said for PTFE boutique "hand made" caps, which may as well be microphones.
There's a weird audiophile fascination with PTFE, whether in caps or cables. Yet it's a poor choice for either application.Many thanks.
Maybe that explains a bit of the reason for changed (improved HA HA) sonics from them, specially inside a speaker.
(it was slight tapping,I didn't hit it with a hammer [yet] )Tapping on something is a good way to diagnose microphonics but doesn't represent a realistic use case for determining the auditory efficacy of isolation devices.
Well, actually it would be quite possible for us to test devices in such way. We once had an industrial client, who was considering to use our isolator for their products. But they wanted to be sure that the final result is in agreement with required specifications. Therefore he gave us the vibration spectrum that was measured at the clients floor, and we should show how our isolator would perform in such condition.What I had in mind was more in line with the type of testing done for aerospace products and such. Put it on a shaker table and see how (if) the output changes as you crank up the vibrations. For audio, measure the output of e.g. a DAC. Transmissibility data will not be understood by the wider audience, and as noted do not translate directly to audibility. That is a function of the component and its sensitivity to vibration.
Immersing in a sound field as @SIY suggested can be interesting and probably more relevant. A shaker table is usually a low-frequency device. I did sound-field testing in the primordial past when I was trying to optimize my turntable's isolation. I had a "silent track" on a recording and played pink noise on my speakers as loud as I could stand and measured the output from my preamp while the disk spun. Later I helped with something similar for flight-rated oscillators when we immersed them in a sound field as well as doing the usual shaker tests. Pilots get vexed if the radar readout dances around during flight, and the astronauts on the space shuttle had similar concerns. Those were the days...
-115dB. Not bad at all!(it was slight tapping,I didn't hit it with a hammer [yet] )
I mean if its so sensitive in a loopback with 30 cm cable,well...
one additional remark that might be interesting, and maybe relevant in this context:What I had in mind was more in line with the type of testing done for aerospace products and such. Put it on a shaker table and see how (if) the output changes as you crank up the vibrations. For audio, measure the output of e.g. a DAC. Transmissibility data will not be understood by the wider audience, and as noted do not translate directly to audibility. That is a function of the component and its sensitivity to vibration.
Immersing in a sound field as @SIY suggested can be interesting and probably more relevant. A shaker table is usually a low-frequency device. I did sound-field testing in the primordial past when I was trying to optimize my turntable's isolation. I had a "silent track" on a recording and played pink noise on my speakers as loud as I could stand and measured the output from my preamp while the disk spun. Later I helped with something similar for flight-rated oscillators when we immersed them in a sound field as well as doing the usual shaker tests. Pilots get vexed if the radar readout dances around during flight, and the astronauts on the space shuttle had similar concerns. Those were the days...
Hello Frank,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.