Best type of metal for turntable platform?

At the moment this platform is for a Project RPM3 with Hana SL. Im planning on upgrading both in the future. I have a wooden floor with a lot of play and too many vibrations. Im currently using a maple wood platform at 16 x 13 x 3 on top of SVS subwoofer feet and was going to put the 2nd metal platform on the bottom (maybe on top) of it. Thought if they were same dimensions and flush it would look and sound better. I was planning in putting something in between also. I have a friend with a CNC machine,  so i can pretty much make any design.

YES! I have both of those issues, especially footfall. One because of the flexible floor and the other from surrounding vibrations. I have to tiptoe to avoid woofer flutter. and because of limited space I have to keep the whole setup in this area. I was ultimately never able to use a subwoofer with the turntable because the floor is so sensitive. I don't use a sub with 2 channel but sometimes I want to crank of the bass. Cannot do wall mount in this area. That was my first choice.

I even replaced the bottom of my whole BDI audio rack with 2 types antivibration pads (one rubber and one with cork) that are for washer/dryers and it really didnt do anything.

what do you mean by footfall?

These are great pointers!

There's crawl space under my floor. SOTA has came up many times for my situation, but I do really like this TT and want to make it work. Even if I wall mount I feel that the flexible floor vibration will creep into the wall.

Well.. yes.. the original question was for the platform.. but since someone else brought up footfalls.. which was always a bigger problem.. why not ask to get as much help on it. Ive asked about it in the past but the info you guys are giving is better than anything ive hearf in the past. Again.. i do have a friend with a CNC machine that can make almost any type of metal platform.. so yes.. any info does help with that.

Look... I'm not knocking the SOTA (except for its looks :). If I dont solve this, then I might consider it. I just didnt want to be limited to ONE turntable in this room. I was considering a VPI Prime Signature in a year or two as the next TT. But with this room the way it is, I dont see that happening. the concrete blocks/wood as a footer does sound like the logical thing to do... So there's noooo other way to deal with a footfall im assuming? Is this why im getting woofer flutter/pumping with almost anything I do?

Ok.. yes.. as much as i said i can never handle my crawl space and would never go under there.. if its for the love of getting rid of vibration for the ultimate analog bliss.. im gonna do it! Im gonna lift this freaking house up. Do i move out as much furniture, etc., out of the room before lifting it? 

andrei_nz

Thanks for the info. Everyone on here has been very helpful. Do you know where maybe I cant find an exact schematic? I know that's asking for too much. He's the type that just needs the measurements and/or plans. 

Its puzzling to me how mini trampoline footers like the Isonoe can can be good for footfall.. I am intrigued though and might try them.  Once it warms up here, from influence of these replays, Im going to get under my floor and add supports to the floor. BUT! If I can find a way out of it.. Ill try it (without breaking the bank).

So I decided on purchasing a Townshend Seismic Platform. Then when it warms up here im going under my floor in the crawl space and going to add supports to the floor. Then I'll ask my buddy to mill the platform.