DIY turntable isolation

Put it in the garage.

 

There was a very good article in Australian Hi Fi that tested different isolation and anti-vibration materials.
Sand boxes were useless as were stone.Solid hardwood was close to as good as anything.I think best was a combination of hardwood,sound deadening high density foam and 6mm perspex.

 

The cheapest and most effective is a thick slab of foam rubber. It looks like hell, bu there is nothing better.

 

Well, I've tried placing a 12" diameter inner tube under the TT. It seems to have reduced the impact footfall has on the tonearm but it hasn't cured the problem. I suspect that - shy of wall-mounting the TT - I'll have to put up with it. The floorboards move quite a bit.

 

I recently dove head first into the vinyl realm and built myself a cool sandbox that i think is worth sharing with the group.
Marble slab sits on top of ground walnut shells about the size of course sand. works great and cost me ~$150 or so and some time to fetch parts around town and some time in the shop!
Cheers

 

This design has mass and sand to absorb higher frequencies but I think I need to incorporate dampers as well. I need to be able to level the isolation table. The feet on the Debut are fixed dampers.
Question, would half'd racquetball a be best placed under the turntable, marble slab in lieu of sand, or under the isolation table?

 

No, he was always clear that you need isolation in more than one plane:

"There are two simple mechanical low-pass filters you can make in order to achieve seismic isolation in multiple axes, that is, seismic isolation in the vertical, horizontal and rotational planes. A simple air bearing made from a minimally inflated bicycle tire inner tube will provide seismic isolation in the vertical axis. Roller bearings will provide it in the horizontal and rotational axes."

http://www.barrydiamentaudio.com/vibration.htm

 

A wall-mounted shelf makes miracles and will make your TT very visible and easier to access. It is the cheapest and most effective method by far. I have my shelf beside the audio rack at a height that makes operating it very easy while standing.

 

Nice job!!!

 

My DP300F would skip easily too when i first purchased. I acquired a piece of high grade carpet padding and placed it under the table. It took care of most, but not all of it. For the hell of it, i removed the oem feet. NO MORE issues.
I know, kinda strange but it works fantastic

 

The wood in my violins sure rings. They wouldn't function very well if it didn't.

One solution that can work wonders is to build a sandbox for the table to rest in. Sand definitely does not ring. I'll be doing just that for a table I'm working on at the moment.

 

I'm a fan of a 3 point suspension from the ceiling, with turnbuckle adjusters. Easy to level. You can counterweight as well, if you don't like the swinging.

 

+1 for wall mount.

 

Violins ring? Wow.

One thing though - for wood to be able to absorb vibrational energy, it has to be a) of hard variety (maple or harder) and b) thick enough - at least 2" for average component and 5" for TT's. Try a 5" thick slab of maple and see if it rings.

 

Racquetballs, cut in half, work even better. Use 3, not 4. Easier to level.

There's all kinds of things you can do...wall mount, sand boxes, foam, inner tubes, pointy feet, marble or granite or other large mass underneath, the list goes on.

There's one method which I have NEVER seen fail, and that's hanging the turntable from the ceiling. If you want to get it over with in one fell swoop, give that a try. If you prefer to monkey around with different methods til you find the one that works best for your particular room/install/turntable combination, have at the rest.

 

Absolutely the wood in my violins rings. Tap on the top and you get one very clear pitch, the back will give a different one (by about a semi-tone if the maker knows what they are doing).

 

3m wrist rests for keyboards or mice. ZERO transmission from the table. I've actually sent the needle skimming the record trying to get it to "sound" thumping the table--meaning, I had to hit the table hard enough to send the needle across the record and didn't get any thump prior. And prior to putting them under--it was SUPER sensitive--the lightest tapping of the table leg or body (I don't mean the turntable, but the table it's sitting on) would result in very loud "whhummp" through the speakers.

If you're buying them new....I dunno--you can buy those 2" feet for about the same money....but, who doesn't have some of these in a closet? Or office closet at work? Repurpose this goop for good rather than landfill, say I.

 

I am a believer in the Herbies Audio Lab products. I think the owner's name is (Steve Herblien? or something like that). This guy knows a lot about vibration control/management and has a Q/A forum on his site where he helps customers. (suggests product selection and management strategies) I was looking into building a custom (experimental) Rega plinth and he gave me some great input and ideas. His suggestions actually required me purchasing less of his products and saved me some cash, not to mention helping me come up with a simpler/better design. He seemed interested in suggesting the best design ideas instead of just seeing how much of his products he could get me to buy. I haven't got around to building the plinth yet, but have used some of the Fat Dots and they do a great job.

I second the suggestion on the wall shelf and I use my Rega shelf with Herbies Fat Dots between the shelf and turntable feet. An elephant can dance on my floor while I am spinning records and I am good to go! I do have sheet rock over concrete walls with Delrin spacers between the wall shelf mounts and the concrete. Concrete is used a lot in construction here instead of wood, so my wall shelf is "rock solid".

 

I used a slab of marble I grabbed from the lawn furniture, serves a better purpose than a beer holder

 

Twenty years ago I made a vibration control device for my turntable using three pneumatic isolators, the Barry Controls SLM1A. I believe that these are still being sold. This device works very well, jumping on the floor (not an easy task at my age) does not affect playback.

I placed the 3 isolators in the box (walnut sides) shown. They are mounted to the bottom using some EAR sandwich mounts (this gives an extra degree of horizontal isolation) and to the top via the screws that come with the devices. I built a slave cylinder for each isolator out of 2" diameter PVC pipe with ends capped and tapped with a valve connector. All this fits into the walnut box/container. Each isolation unit (SLM1A + slave cylinder) is connected to a Schrader valve on the side of the box. The top of the box (plywood) is covered with a 1/4" sheet of EAR isodamp and a 2" thick marble slab sits on top.

The total 1995 cost was about $400. I don't think it would cost much more now, and I'm sure that expert diyers could improve my construction.

 

I got one of these when I was experiencing some bad footfall and rumble issues.

http://www.smartfurniture.com/products/Sumo-Floating-Shelf.html

Cheap and solved my problem completely. Really sturdy.

 

Why not? because it actually is not acoustically dead. All things vibrate. The resonant frequency of anything will depend on the dimensions and stiffness. The stiffer the material the higher the frequency of the resonant frequency. So to really *isolate* a turntable that is sensitive to vibrations starting at 20 hz you need a suspension that has a resonant frequency well bellow 20 hz. That requires a very compliant component. A spring, a magnetic suspension, an inner tube, a bearing with a low resonant frequency etc. etc. Mass loading will reduce the amplitude of vibrations because it simply requires mor energy to move more mass but it won't stop vibrations by itself. You need a suspension of some sort and it needs to have a resonant frequency well below 20 hz.

 

Everything rings.

 

Everything vibrates and everything damps vibrations. It's a matter of degree on both counts. All one does really need though is a suspension that has a low enough resonant frequency in all three axis. the bearings do the job on two of the three axis provided they are smooth enough not to actually contribute added vibration.