Vibration Issues / Turntable Decisions

handymann
@Geoffkait - I tried the bungee cords and besides my near disaster, I found the TT, not being uniform in weight distribution, wouldn’t be level with the bungee cords. Guess I could have weighed my platform with weights to offset the difference, but I just went with metal cable and springs. I’m still not primo as get an acoustic bass load up, when playing heavy bass LP’s. I can listen to regular to high dB levels, but can still get a cartridge feedback with heavy bass albums. Any recommendations?

>>>>The trick is to match the load with the proper spring rate. For example the cryo compression springs I sell are rated at 15 lb/in. Since my springs are only 1.5” uncompressed so you only want to compress them 1/2” or 3/4”. 4 Springs would be ideal for a total mass of about 30-34 lb. Five springs for a mass of 40-50 lb. As you suggest the mass needs to be equally distributed to keep things level. My new super stiff springs will support very heavy loads such as big VPI and Verdier turntables and Classe and other big heavy amps and subwoofers. I suspect when suspending turntables the dynamics of the spinning platter could be an issue. The mass distribution is probably an issue. I would try the cables without the springs and see what happens. Stiffer is preferable to too springy.

When using bungee cords the secret is (1) to use bungee cords with the correct spring rate for the application and (2) ensure that all connections are secure. 😛 Timely tip: if you go bungee jumping don’t secure your own bungee cords. 😀

Bungee cords is a preferred inexpensive but effective method of vibration isolation oft used by Universities to avoid the high cost of effective isolation platforms. Bungee cords can provide many directions of isolation, including rotational directions. Where’s the beef? 🍔

I’d opine it’s a little more complicated. The resonant frequencies of tonearm, cartridge and platter which are circa 10-12 Hz means they’re liable to be affected by seismic I.e., low frequency vibrations including, but certainly not limited to, those produced by footfall, subways, traffic, and Earth crust motion. In addition, this seismic vibration is in six (count em!) directions, including horizontal plane and vertical and a bunch of rotational directions. Therefore, the walls are moving too. The whole house is moving in all 6 directions! You can run but you can’t hide. Everything is relative so for trampoline floors the wall might very well be better than the floor. But there’s really no substitute for real vibration isolation, i.e., decoupling.

The same principles do apply to turntables. The same principles also apply to amplifiers, preamplifiers, CD players and speakers. Bungee cords is an excellent example of mass-on-spring physics, upon which almost all audiophile isolation devices are based. Mass on spring acts as a mechanical low pass filter. Bungee cords operate the same way as steel springs and air springs, air bladders. Many audiophile isolation devices such as Vibraplane and Minus K come to us directly from atomic microscopy and from the mother of all isolation companies, Newport Corporation. Minus K in its first incarnation - or would that be carnation? - was Newport's Sub Hertz Platform.

roxy54
I said decoupling not damping.

I was responding to the poster previous to my comment. I am pro decoupling and pro draining and to a lesser extent pro damping. In combination, not separately.

I already acknowledged some racks and stands are not too bad. And I never mentioned anything about damping. I trust you aren't confusing isolation with damping.

Viva la difference! 😀

Two different spring systems can be used effectively only if their respective resonant frequencies are separated in frequency by a sufficient spacing. Otherwise the two spring systems will interfere. It would be like a car traveling down the road with two sets of identical springs for each wheel. It would be a very bumpy ride. LIGO isolation included dual layer heavy mass-on-spring systems. So there's no doubt this technique works or why.

Roxy
Geoff,

No, I don't "follow". You're still saying that most racks and stands are "terrible", and that is a silly comment.

OK. let's try a different approach. Most racks and stands amplify structureborne vibration. Which is terrible. That's why moving electronics from the rack or stand and placing them directly on the floor usually results in better sound. Even without any isolation. Now do you follow?

🏃.  🏃

The trouble with turntable springs is their resonant frequency isn’t low enough to do any good in certain situations. Such as this one. 🙄 My advice - remove the springs and get yourself some real springs.

Roxy, obviously whatever stand or rack the guy has isn’t working. Of course I’m not saying all racks and stands are terrible, just most of them. Follow?

Ditch the stand. Stands and racks are bad news.