Suspensions on turntable...really effective?

Diamonddears, I'm no mechanical engineer, but a spring has a resonant frequency (it's "rate"), above which it isolates whatever is sitting on it from whatever the spring itself is sitting on, and below which it does not---the mechanical energy passing right through the spring, un-attenuated. The isolation resembles an electronic filter, with a roll-off slope beginning at the center frequency.  A turntable suspension, therefore, should have as low a resonant frequency as possible, 3Hz being an attainable number. The lower the desired frequency, the "looser" the suspension, and the slower the table will bounce when pushed down upon. A table tuned to a low resonant frequency will have soft springs, like an old Cadillac. 

I could be wrong, but I doubt you could find any white paper specifically on turntable suspension. The audio industry just doesn't seem to publish that detail. You would have better luck looking into industrial products like TMC: http://www.techmfg.com/products/at_a_glance.html

As a designer of isolation devices since Jesus was a Boy Scout I would just say the spring rate in pounds per inch is related to the resonant frequency of the iso system by the equation, system resonant frequency Fr equals the square root of (total) spring rate over total mass. So the more springs employed the higher the total spring rate (the stiffer the suspension) and the higher the system resonant frequency. The way I obtained extremely low resonant frequency for my sub Hertz platform was use only one spring. Whaaaaat? Most spring systems are too stiff to be effective dealing with extremely low frequency vibrations that are the issue, the ones produced by footfall, traffic, the speaker feedback, Earth crust motion. Even iso systems that provide Fr of say 3Hz are not really that effective when it comes to dealing with extremely low frequencies since the iso system acts like a mechanical low pass filter and won’t attenuate very effectively much until the frequency of vibration reaches say 15 or 20 Hz. How to easily measure the Fr of the turntable suspension.  Push up and down on the (suspended) turntable and time the motion with a stopwatch to obtain cycles per second. 3 Hz is a relatively slow undulating motion.  A more rapid motion will be up around 8 Hz or whatever, which is too high to be effective against very low frequencies.

It can be plucked while the record is playing, and so far no listening can tell I am doing it.

lol
Sorry for the error and the others in my previous post.

That’s it... out with these new Arabica beans my wife bought me - in again with the Costco Zavida. The Arabica brand aren’t kicking in fast enough.

correction to the previous post.

It can be plucked while the record is playing, and so far no "one" listening can tell I am doing it.

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Geoffkait - As a designer of isolation devices since Jesus was a Boy Scout

@Geoffkait and all manufacturers, designers, dealers, distributors, and all those in the audio business...... posting on Audiogon.

Why don’t you guys take the opportunity to show your company name in your monikers box so all like myself, non professionals, can see your professional affiliation?

Just sayin...

Kudos to those like PBN Audio who have already taken this opportunity.