What is under your TT, cheap islolation?

Fishwater,
Like you, I built a sand box with a floating lid to go under the TT. If you are setting the box on a shelf or other flat surface, I suggest you elevate each corner in order to minimize the box from absorbing any shelf resonances. A simple solution is to drive a small brass screw up into each corner of the box from underneath. Leave the entire head showing, and it will act as a small spike.

My sandbox didn't isolate as much as I would like. It was a fun project but I still have the skipping problem. Short of hanging the TT from a wall shelf what can I do?

I was afraid of that. The problem is the sandbox is great for vibrations but, obviously, it is bouncing with the floor as well. As others have mentioned the real solution is to completely decouple from the movement of the floor. You could try moving to a wall or corner that has a load bearing structure beneath it in hope that the floor bounce won't be as severe in such a location. Otherwise, it's either the wall shelf or hanging it.

BTW your sandbox could still be of benefit on a shelf.

Don't give up!

Dan

You have two other solutions make the floor stop bouncing or get a turntable that is immune.

a. You seem to shy away from any type of structual reinforcemnt to your house. Heavily padded carpet might absorb some of your footfalls.
b. Most turntables today have no suspension at all. Those that do are not designed to deal with the magnitude of oscillations you decribe.
c. You need a turntable that floats the arm and table together. Even though your floor is bouncing the arm and platter "float" together and the cartridge remains in the groove. Sota and Linn make such tables.

Ultimately a major floor bounce is really an unacceptable situation for a turtable. For example a cd player has error correction and will continue to play even when it is mistracking. A turntable has no such correction. Even though it is still playing, it is still mistracking.

The only real solution is to stop the floor from bouncing or a wall mount.

I don't really know how to support the floor better. My room is located over my garage & I use the garage for storage of vehicles. I couldn't put a bunch of support collumns under the floor because it wouldn't allow me to park any vehicls inside.

At this point I would rather not put up a wall shelf but it seems to be my only option.

I am pleased I made the sand box, it was fun & came out great. I plan on using it under the turntable regardless so it wasn't a waste.