Best isolation platform for a turntable with suspension?

I just had another one of those moments where its hard to stop smiling.  I have my TT on a wall shelf and have had a chronic issue of getting feedback/rumble at higher volumes.  I got used to it and hadn't tried anything until today when I opened my Delos box.  I picked up the 22 in wide by 1.75in thick used from The Music Room.  Wow!!  The rumble is gone!!  I am only 3 songs in but am so excited...I can't wait to experiment more and do some critical listening later this evening.  What gave me confidence in this working was that I would only apply slight upward pressure on my plinth and the problem went away.  There are many options out there but this beautiful walnut block looks pretty sweet and is very reasonably priced for the market.  Happy listening and kudos to isoacoustics!!  

A spring suspension engineered into a turntable is the best isolation. You already have that. You probably just need to get a more rigid rack underneath it. Cheap flimsy racks (e.g. VTI) are the absolute worst enemy to quality turntables. At least 4 posts, NO to the stackable / modular shelf designs, look for a wider footprint, don’t go too tall. And filling the legs with sand / shot won’t fix an inadequate rack. Honestly you cold probably do a lot worse than your current support, but it also wasn't designed for high-end turntables. The Symposium racks might be worth a look. 

Throwing isolation products on top of an improper rack support isn’t the way I’d go. As mentioned before, you don’t want to stack spring systems. And if your flooring is extremely poor then you’d have to fix that before anything else but sounds like you’re OK there.

OP, Symposium also make cup and rollers.

You might also look at Lessloss Bindbreakers, no direct experience myself but I have read good things including use with turntables 

Your Avid TT, utilizing a floating sub-chassis, would not do well with the Symposium Segue ISO for the very reason that internal springs combined with external springs is not a good combination as they would "fight" one another.  My suggestion is to get in touch with Peter at Symposium and discuss their other options.  The standard Segue platform (no springs), when "coupled" with your TT is what makes for the performance enhancement.  The platform uses a constrained layer design and is an excellent isolator itself, preventing external vibration from making it's way to the TT.  But the other half of the equation is to drain internal vibration out from the TT.  The basic premise of the floating sub-chassis is to isolate the playing mechanisms of tonearm/platter/cartridge from the vibration of the motor and main chassis, as well as that from external vibration.  However, it isn't a perfect solution and there still remains internal vibration that, ideally, you want to drain from ever reaching the playing mechanisms.  A direct coupling with the TT, known as a mechanical ground, is the solution for this.  With Symposium products there is a less expensive coupler to use, such as the Fat Padz.  But the far superior device is the Rollerblock Jr or Jr +.  The combination of an isolation platform with a mechanical ground delivers outstanding results.  Depending on the size of the platform (there are several sizes available to accommodate different sizes of TT) and your choice of mechanical ground device, the combined cost can range from $250 to $550.  Everyone has their own opinion on cost/value return on investment.  For me, spending $600 on a Segue ISO and Rollerblock Jr + was an excellent value in what I got for what I spent.  The results went beyond my best expectations.  Money well spent.  
Best to you on achieving your performance solution.  Be healthy.

I have tried granite, MDF, cork, rubber and all the variations. I finally got a 4 inch thick maple block and it sounds the best. I have read those EXPENSIVE electron microscope platforms are the bomb. But if you only had so much money to use then you would probably be better off getting a better TT. LOL.

Thanks for the suggestions all! Lots to think about here.

Re: Symposium - I looked at their stuff but since it uses springs I was thinking that it wasn’t going to do much for me since the Avid already uses springs as well. But maybe I’m wrong about how these things work.

Leaning BDR at the moment but looking through these all.

Suggestion:

Place your turntable on a platform made of slate 30/40 mm thick and square on plan. Under the slate use three Ingress Engineering cup and rollers in a equilateral triangle configuration.

I predict excellent results from this low cost solution.

I own Symposium Acoustics products and found them to be amazing performers for my turntable.  You can call them directly and speak with the owner.  Peter is his name.  He is very bright on the subject and is very willing to help you get the correct product for your particular needs.  He makes a variety of products to choose from and, depending on your budget, will match the best performance possible.  Easy to find the company information via a Google search.  They are located in New Jersey so understand that, relative to time zones.
Good luck to you.

From your system pic it would seem that the large flat screen TV is destabilizing the Sanus (lots of weight to the back legs) as well as sending additional vibration through it (the Sanus).

I would simply wall mount the TV, decoupling it from the Sanus.

DeKay

SYMPOSIUM QUANTUM SIGNATURE is the best get one ASAP!!

I used a wall mount many yrs ago just awful results. While playing music with bass just place your hands on the wall where your wall mount would be and "feel" the vibrations. Even if placed in studs did not help YMMV

Mass loading a target vw1 turntable shelf with marble also works fine. 
Occasionally can find used if necessary.  You asked for best so this may not be appropriate. 

Apollo based in the UK makes a nice turntable shelf, both single and double. The double provides an additional shelf below for a phono preamp or what have you...they are built using heavy duty welded steel with your choice of glass or wood for the shelf/shelves. My single is mounted to an outside wall in basement which is concrete covered in 2x4's & drywall. Zero vibrations and footfalls. They are not too expensive, look nice, and work well. 

If you have not come across the CS2 footers from Critical Mass Systems, it may be worth your while to do so.  I have used almost every vibration reduction tech around.  These make the rest look like toys....let's say in my opinion it's not even possible to make comparisons.

Downside: they take 300 hours to 'burn in'
Sound awful first few days, till they settle into full isolation mode for your specific room/equipment.  I don't understand how this happens, it's something to do with entropy!

Once it does though,  it's as if you suddenly doubled or trebled the money spent on your system.  

Home Depot or Loews,

buy a 12x12 or larger or the size u need, slab of granite, or a piece of  tile 2-3 inches thick, and done!
 Cheap and is sturdy for a TT!

 I have a recently new marble slab cut to perfection, at 15x15 for my SL-12OO mkII. 
 WORKS GREAT!

 Or hit a home decor place like bed, bath n beyond and pick up a nice 4 inch cutting board (maybe 50-70$) for a nice one.

I use two 4 inch cutting boards which I sanded a little bit, stained then with cherry stain, And use for amp stands, they look great, as wood is always in style!
as is a 3-4 inch slab of granite, or marble, or anything heavy which don’t let vibrations in.

 Enjoy.

I was having vibration problems with my turntable lying upon a Levon equipment rack which is pretty sturdy but the floor is synthetic wood on I imagine concrete as it is the first floor of a three floor apartment complex . Even though my turntable is the suspensionless type very small movements on the base of the Levon would be picked up by the turntable smearing and distorting the sound . 

I'm on a  fixed income being retired so I was looking for an inexpensive solution if there was one . Saw at Walmart a wooden butchers block think it is maple about 1 1/2" thick and long and wide enough to acomodate my turntable with some space to put my turntable accesories as cleaning brush and what have you . They whole affair for 15.00 on special I admit .

Got me some Sorbothane round pucks , 6 of them for 32.00 dollars ( googled it and found them ) . Took the pucks and accomodated them two at the time in a triangular configuration under the butchers block .

Behold a miracle happened . Now I can literally strike with force the base of the Levon with absolutely no problem . The turntable is now totally inmune to vibrations . All for less then 50.00 dollars , and it looks good as the block looks as if it were made for the turntable .

I don't know if it will work with a suspension turntable but the physics involved tells me it should . Take care and let us know how you solved the problem . Stay face brother .

I use  marble  I got from local counter top guy...I love it.

I have my Basis TT on top of a large BDR shelf.

My reference TT without suspension rests FLAT on top of a CMS shelf, it works great.

Good luck,
Jose

I did a whole lot of research into this, and tried a lot of different things, all during which time my Basis table was used on the floor. Can't recommend the floor as being very convenient. It is however pretty much the gold standard for turntables. Very hard to build a rack as good as being on the floor.  

Hard, but not impossible. This does the trick. https://systems.audiogon.com/systems/8367
Like slaw recommends its heavily BDR. Like Mike mentioned its mass loaded, uses sand, and is incredibly cost effective. The whole rack including granite can be built with a minimum of tools for only about $300.  

The whole rack is over 700 lbs. But it is modular design. You could build just the top shelf with or without the granite and put it on top of your existing rack. Then add the rest later. Or not. 

If you do build the whole thing, or even part, I am sure you will find it can be done better. But for thousands, not hundreds. 

I use a wall mounted rack with a Mapleshade 2" maple platform for my Avid TT in my second story wood floor room. This works well for me.

DYI a wall mount shelf for your table could buy one too but easy enough to make a shelf.  That will help greatly. Most likely nothing else required after that.   

It looks nice and has an integrated mount for my 65” TV. Long term i absolutely want to replace it, but during this pandemic there’s no way I could do anything with this rack by myself.

the good news about that Sanus is that it’s wide with a broad base and not tall. i’d say mass loading the Sanus would stabilize it and reduce resonance. it’s never going to be really stiff, but you can improve it’s stability. what you are trying to do is give your Avid suspension a firm base for it to work.

the cheap way would be a piece of thick (1/2"-1") solid stainless steel on thin rubber gaskets. or a sandbox. both can be somewhat non intrusive to the look of the rack.

better but more expensive would be a Vibraplane air bladder shelf.

but the last thing you want to do is add more in-stability with any sort of decoupling footers. those; combined with the Sanus and the Avid suspension would add resonance and smear to the sound, not reduce it.

as always; you have to try things and listen. an easy way to try the mass loading without spending a dime would be to get something heavy and dense and place it between the Avid and the shelf and listen. if it helps then get something nicer to look at. you could use bricks or a stack of large tiles. anything that won’t move around at all. just to see where it goes. your thought is to see if calming the Sanus improves the sound. it should.

when you are ready to get a better rack, then that new rack should provide the proper shelf for a whole different approach.

I'm a big fan of BDR.

@mikelavigne It’s a Sanus JFV65: https://www.sanus.com/en_CA/products/furniture/jfv65/

It looks nice and has an integrated mount for my 65” TV. Long term i absolutely want to replace it, but during this pandemic there’s no way I could do anything with this rack by myself.

@slaw it would be placed on top of my rack

Roller bearings will not adversely interact with your table’s spring suspension, and will provide isolation in the lateral planes (the springs do well in the vertical). Great ones are available from Ingress Engineering in Canada, Symposium Acoustics in the U.S.A.

sounds like your floor is pretty good, that’s a big positive. typically that is where you run into limitations.

what rack are you currently using? you mention it’s not the best. that might be where you start first. a good rack does not need to get crazy expensive.

whatever shelf or footers you add will essentially become part of that rack and the effectiveness of those added items will be limited by the rack.

Where would the isolation platform be placed?

Floor type is wood, probably over poured concrete. It’s an apartment building so i can’t be sure but it’s really solid which makes me think concrete.

What is your floor type?