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For many years now I have been plagued with floor bounce problems when playing LP's. My wooden suspended floor is bouncy. All the turntables I've had in the past have had susceptibility to footfalls. The suspended sub-chassis tables, like the AR-XA and Thorens TD-160, have been the worst offenders. The Thorens TD-160 was so bad that the cat jumping out of it's chair would set it off. It was difficult to tip-toe across the room without causing groove hopping. I played with the set-up for months and couldn't make it better. The old Duals with the stiffer under-the-chassis springs were better at this, but you still had to be a little careful. The best I had found before was an old Garrard Synchro-Lab 95B. This was of the same suspension as the Duals, but lighter built in a cheap plastic plinth. Although it tracked well, the sound wasn't as good as the Duals or Thorens, or even the AR.Today I was playing with my 55 pound Siberian Husky, Isha, on the living room floor. I wasn't even thinking about the record playing. It was an impromptu thing that took off without thinking. We were romping pretty heavy. I became aware of the record playing when the stereo cabinet door popped open under the turntable. The record kept on playing like nothing was happening whatever. We both had been stomping and hopping around quite heavy. I am now more convinced than ever that mass is the key to good stability and vibration isolation. The very massive plinth is firmly coupled to the turntable's chassis. The whole thing sits on a piece of rubber carpet backing, which is the only suspension it has. It's got to be the mass. I can't think of anything else that would be doing it. There have been a lot of discussion the last few years about massive plinths being the key to good isolation, but this is the first real evidence I've had.I'm a believer!Dave
John,The stuff I'm using isn't shelf liner (or if it is, it's like none I've ever seen). It's padded rubberized carpet liner about 3/8 to 1/2 inch thick. Quite spongy. It has a pink and blue speckled appearance. I have it covering the entire area under my plinth. With any kind of solid mounting to my cabinet I was getting feedback howl through my sub-woofer (which goes flat to about 22 Hz). Inserting the rubberized backing completely eliminated this with no bad effects. My floor is extremely bouncy and, in my 24 years of living here, has never allowed vinyl playback without footfall problems. Now I can jump around hard enough for my magnet-latched cabinet doors to pop open and the record playing doesn't even cause the speaker to oscillate noticeably. I'm convinced something interesting is going on here... Dave
What about trying the inner tube (air bladder) instead of just the rubber? http://sportsbay.com/bituinpositw.htmlI got a couple of these that I am going to play around with. 16" also happen to be my 5 year daughter's bike tire size in case they are useless.
Quote from: hurdy_gurdyman on 12 Oct 2007, 05:46 pmJohn,The stuff I'm using isn't shelf liner (or if it is, it's like none I've ever seen). It's padded rubberized carpet liner about 3/8 to 1/2 inch thick. Quite spongy. It has a pink and blue speckled appearance. I have it covering the entire area under my plinth. With any kind of solid mounting to my cabinet I was getting feedback howl through my sub-woofer (which goes flat to about 22 Hz). Inserting the rubberized backing completely eliminated this with no bad effects. My floor is extremely bouncy and, in my 24 years of living here, has never allowed vinyl playback without footfall problems. Now I can jump around hard enough for my magnet-latched cabinet doors to pop open and the record playing doesn't even cause the speaker to oscillate noticeably. I'm convinced something interesting is going on here... Dave Hey, that's pretty cool...I don't think I'm aware of that particular product. A friend growing up had carpet stores (he was Armenian, so it was close to his roots in that)...back them they used felt or jute as under padding. The carpet world has moved on since then, it seems....Super that you found something that works for you, Dave...and at such reasonable costing
ya, i have seen that stuff, under commercial carpet installations; never tried it for other uses, tho. if it works... when i prewiously had foot-fall problems, the only way i was ever able to get rid of it was to mount the turntable to a shelf on a wall...doug s.Quote from: hurdy_gurdyman on 12 Oct 2007, 05:46 pmJohn,The stuff I'm using isn't shelf liner (or if it is, it's like none I've ever seen). It's padded rubberized carpet liner about 3/8 to 1/2 inch thick. Quite spongy. It has a pink and blue speckled appearance. I have it covering the entire area under my plinth. With any kind of solid mounting to my cabinet I was getting feedback howl through my sub-woofer (which goes flat to about 22 Hz). Inserting the rubberized backing completely eliminated this with no bad effects. My floor is extremely bouncy and, in my 24 years of living here, has never allowed vinyl playback without footfall problems. Now I can jump around hard enough for my magnet-latched cabinet doors to pop open and the record playing doesn't even cause the speaker to oscillate noticeably. I'm convinced something interesting is going on here... Dave
My studio has built in countertops made from 2 layers of 3/4" HDF, the outer layer oak veneer. I have found the best foundation for a table is mass. Four of my tables sit on this countertop and I have zero issues with any of them. I can even walk on the countertop whilst an album is playing with no regard for skipping a record. The countertop has substantial bracing legs for support. This is my design when I built the house because I have had problems in the past.I'm sure other ideas have merit as well.
I suspect that Dave's piece of carpet underlay is acting like a well-damped spring. If you want to experiment with foam pads under a piece of equipment, a useful starting point is to size the pads so that they deflect (squash) somewhat under the weight of the equipment, but not too much. Don't let them squash to less than half their original height.
FWIW - When I had tight space for my rig in college I suspended my TT from the ceiling using plant hooks, some heavy monofilment fishing line and a cutting board for a shelf. It wasn't pretty but I had zero vibration issues...
