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Suspensions on turntable...really effective?

Been wondering about this, so did some research, but was surprised I couldn't find any that categorically says that turntable suspensions really isolate/substantially reduce outside vibrations, resonances, etc.

Any reference out there you can point out?

Cheers
diamondears
geoffkait's avatar
geoffkait
23,365 posts
 
  • The subwoofer puts out what maybe 20Hz if you’re lucky. So the iso system doesn’t actually have to be too heroic for subwoofers. The resonant frequency of the iso system for the sub would only have to be what about 8 or 10 Hz to be effective at 20Hz and above? The idea of course is to prevent subwoofer cabinet resonance to feed back to the rest of the system via the floor. The Super Stiff Springs will provide between 2 and 4 Hz resonant frequency for the isolating system depending on total mass on springs. So, let’s say your subwoofer weighs 100 lbs. For the lowest resonant frequency of the system you would use three Super Stiff Springs but since the subwoofer’s lowest frequencies aren’t really an issue - as they are for components when seismic vibrations are involved - four springs are recommended under the subwoofer for stability. You still have to isolate the rest of the components from seismic, subways, footfall and tap, i.e., all sources of structureborne vibration. But by isolating the sub you eliminate one big contributor to structural vibration in the room. 
lewm
12,985 posts
 
Dear Ct0517, To answer your question, I have two systems.  In both cases, the drivers are based on electro-static principle.  In one case, yes, the ESLs are driven by OTL amplifiers that do generate a lot of heat, but never enough to raise the room temperature by 10 degrees Fahrenheit (about 5.5 degrees C).  And no, I have never perceived that the heating of the room, such as does occur, has any effect whatever on the sound. (The other system is based on Beveridge speakers which are driven by Beveridge direct-drive amplifiers built into the base of each speaker.  Thus no audio step-up transformer in the signal path. Those amps use a solid-state input stage and tube outputs [4 per chassis] that have no measurable or perceptible effect on room temp at all.)

diamondears OP
16 posts
 
Geoff, if I isolate the turntable itself, do I need to isolate the subwoofer? 
geoffkait's avatar
geoffkait
23,365 posts
 
It would be a good idea to isolate both the subwoofer and the turntable and all components really. The attenuation of passive iso systems is around 6 dB per octave. But you’re right, the subwoofer’s lowest frequency will be almost entirely attenuated by the turntable’s iso system, assuming a 3 or 4 Hz iso system that’s 99% effective by the time you get up to 20 Hz. The most aggregious frequencies for the turntable are circa 10-12 Hz since they would excite the natural frequencies of the tonearm and cartridge.
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