Looking For Turntable Isolation Techniques & Ideas

[garymd]

Travis,

My TT will be setup in a carpeted room. The foundation is just typical residential slab-on-grade.

What I liked about the link was it's reference to F1, I have not read through it thouroghly.

Personally, I would never use a wall mount type system for any mechanical music device, no matter how well built, and thought out. The only exception might be an infinitely rigid concrete wall.

If you have a concrete floor, a wall mount is probably not necessary but in all other cases, it's probably the best way to isolate the table. What do you have against wall mounts Gilbert? I've seen them in action and they work beautifully.

Paul - My gear is in one room while my speakers are in another. It happens to be out of necessity until I expand the finished room in my basement. At that time, all my gear will be moved into the finished area along with my LPs. I'll probably leave the cleaning machine in the back however.

I must say that having my table on a concrete floor and isolated from the rest of the house is great. Short of a high powered explosion, there's no way to disturb an LP while it's spinning.

[kaiser SET say]

Gilbert, my last house setup was in the Sunroom of a house built in 1921 with plaster over slat walls!

Isolation worked like a charm as you could (Seti can attest to this one) jump up and down in front of that rack and the table did not catch a bump one!

[kaiser SET say]

I have recently moved and have a new set of isolation challenges but I think (I have used this one in the past also) that I'm going to go with the suspended setup just above the left side of my rack behind the speakers[]

[Wardsweb]

For what it's worth I will post again about the isolation sandbox I

built. It is both an isolation and dampening device. I built this

isolation sandbox when I was running a Rega Planar three and high

output cart.

There was an audible rumble before using the sandbox. After, dead

quiet. I still use the isolation table with my Clearaudio Champion II,

but don't know that I need it anymore, can't hurt though.

http://www.wardsweb.org/audio/isolation_table.html

[Colin]

In the VIP that I made, the 30-lb block really prevented the tennis balls from moving. In the Ginkgo, the acrylic top has sides that come down, but do not touch, the plate. The plate has dimples to hold the balls. I also banged it to test it and even when knocked so the top is twisted 45 degrees, the balls can not come out from under the top plate.

Their site and tests on it at Stereophile show the amount of reduction that one racquet type ball per 10 pounds can make...

[kev313]

In the VIP that I made, the 30-lb block really prevented the tennis balls from moving. In the Ginkgo, the acrylic top has sides that come down, but do not touch, the plate. The plate has dimples to hold the balls. I also banged it to test it and even when knocked so the top is twisted 45 degrees, the balls can not come out from under the top plate.

Their site and tests on it at Stereophile show the amount of reduction that one racquet type ball per 10 pounds can make...

Really? That doesn't line up with my findings at all. Perhaps your dimples are deeper than mine. I mean that in a manly audio sense, of course.

[fini]

I have recently moved and have a new set of isolation challenges but I think (I have used this one in the past also) that I'm going to go with the suspended setup just above the left side of my rack behind the speakers[]

Tim,

I like how you've isolated the tweeter and squawker from your La Scala!

[fini]

I still like my idea of magnetically suspending the turntable in a vacuum chamber. No sound waves hitting the rig. It'd probably clean your records, too. I might try to cobb something together here in my lab, with my shop vac (6 HP!), or Cathy's Seal-a-Meal. I think I have enough magnets on my fridge.

[BillH2121]

I moved my Scout TT to a cheap audio rack a few months ago and the change in sound was surprising and somewhat counter-intuitive. I previously had my TT on a very heavy brass and glass table on a carpeted slab floor. On the table I layered foam computer mouse pads, a 30 lb garden tile, mouse pads, and then a two-layered maple cutting board with TT on top. When I got the audio rack, I noticed it was primarily wood with a steel tube inner frame and glass shelves sitting on rubber posts. I expected the sound would be horrible as is (glass shelves and all) - BUT, it seemed as if the sound opened up with added detail not present with the other set up. It wasn't a slight difference, it was a big difference even my wife noticed without my comment. It shouldn't sound that good without all the dampening, etc, but it does and I'm not going to mess with it.

[jazman]

I moved my Scout TT to a cheap audio rack a few months ago and the change in sound was surprising and somewhat counter-intuitive. I previously had my TT on a very heavy brass and glass table on a carpeted slab floor. On the table I layered foam computer mouse pads, a 30 lb garden tile, mouse pads, and then a two-layered maple cutting board with TT on top. When I got the audio rack, I noticed it was primarily wood with a steel tube inner frame and glass shelves sitting on rubber posts. I expected the sound would be horrible as is (glass shelves and all) - BUT, it seemed as if the sound opened up with added detail not present with the other set up. It wasn't a slight difference, it was a big difference even my wife noticed without my comment. It shouldn't sound that good without all the dampening, etc, but it does and I'm not going to mess with it.

Merely adding "more" dampening does not insure better sonic results.

Klipsch out.

[kaiser SET say]

It's all done with mirrors Fini[]

[Gilbert]

What do you have against wall mounts Gilbert? I've seen them in action and they work beautifully.

Relative stiffness. A typical stud wall with 1/2 of gyp on either side (no matter how many nails) is almost always going to be less stiff, and therefore, more easily influenced or excited by loads than the foundation supporting them.

The only exception in favor of a wall mount (IMHO) would be a TT setup that's located near the center of a room (i.e. mid span on the floor joists) on a pier and beam foundation.

[LarryC]

A typical stud wall with 1/2 of gyp on either side (no matter how many nails) is almost always going to be less stiff, and therefore, more easily influenced or excited by loads than the foundation supporting them.

Are you assuming that the rack is only mounted on wall board, or that at least one side is screwed into a stud? One side of mine is screwed into a stud with very long screws; the other is fastened to the 1930's plasterboard wall. I would always try to fasten at least one side directly to a stud. Anyway, I don't notice a problem, tho' maybe one is there.

lc

[Travis In Austin]

What do you have against wall mounts Gilbert? I've seen them in action and they work beautifully.

Relative stiffness. A typical stud wall with 1/2 of gyp on either side (no matter how many nails) is almost always going to be less stiff, and therefore, more easily influenced or excited by loads than the foundation supporting them.

The only exception in favor of a wall mount (IMHO) would be a TT setup that's located near the center of a room (i.e. mid span on the floor joists) on a pier and beam foundation.

Gilbert,

That was the reason I asked about the construction of your home, and when you indicated that you were on poured slab I told you in my opinion you would be best off getting something heavy, like Billy Bags, that tied into the floor. Pier and beam, or a floor with joists are not very suitable for turntable stands on the floor. My media room is on the second floor, and vibrations from foot falls travel all across the room. It would be just fine if I had a floor stand, it is just that no one could walk in the room. Not very practical. Mounting it on the wall, at least for me, totaly isolated the tt from the floor. I can now jump up and down on the floor with no effect whatsoever on playback. During the Texas gathering at my house we had five or 6 people at a time in that room, coming and going, sitting and standing, and this never had an effect. If the tt had been on some type of floor stand we would have had plenty of hops, skips and jumps.

Luther, (Wardsweb) lives in an single level home. I am not sure if he is on a slab or pier and beam, but based on the age of his home I would suspect it is pier and beam. It is also a beautiful wood floor. His turntable sits on a large crendenza, a beautiful piece of furniture. From listening to his system, with foot traffic going to and fro, he was also able to get great isolation. His home made sand filled isolation box works great, I can testify to that. He also uses ball bearing isolation pucks between his crendenza and the isolation box. He was been able to avoid the ugly rack being stuck to the wall like I have. He can tell you much more about it, and if he has a slab or not. If he is on a slab it would explain why he gets such great isolation and vibration control.

So I think it all depends on what you have to work with, and in a second floor room with lots of foot vibration you can get great isolation and vibration control very cost effectively with a wall mount.

At least it has worked out this way for me.

Travis

[fini]

The difference, though, is that people don't walk on the walls (unless you're in a Gene Kelly movie).

[Travis In Austin]

A typical stud wall with 1/2 of gyp on either side (no matter how many nails) is almost always going to be less stiff, and therefore, more easily influenced or excited by loads than the foundation supporting them.

Are you assuming that the rack is only mounted on wall board, or that at least one side is screwed into a stud? One side of mine is screwed into a stud with very long screws; the other is fastened to the 1930's plasterboard wall. I would always try to fasten at least one side directly to a stud. Anyway, I don't notice a problem, tho' maybe one is there.

lc

Larry,

As you pointed out to me a long time ago, the Target wall mount has mounting holes 16" apart and so both sides of mine are into studs with 2 and 1/2 beefy would screws. A friend of my who lives in a single level pier and beam home with wood floor uses a wall mount. The home was built in the 50's and the studs are not 16" apart. What he did that seemed to work great was he got a large piece of wood that he finished to look nice, it is about an inch or inch and a half thick. This was large enought to be fastened to the studs, maybe 20" across. The then mounted his rack to the wood. He is still decoupled from the floor and has not foot fall vibration issues. THe things work great, but I am not convinced that the hugh amount of extra money is worth the extra price of a Grand Prix unit, I would like to see one of those actually in use.

Travis

[LarryC]

Travis,

Thank you and glad things have worked out well for you. I do think the 2-drawer filing cab under my Target makes it a little less conspicuous.

Is my place pier-and-beam? -- I have a basement and joists across the ceiling, so I suppose a jouncy main floor where my things are is foreordained. However, there are three brick piers in the basement supporting what look like hefty beams running lengthwise under the joists, supporting them in the middle of their run. Could be a lot worse, I expect. Anyway, is that pier-and-beam?

Larry

[fini]

Yep.

My house is "pier and beam," as well. Built in the mid-70's (20th century ;^) it has a perimiter foundation under which are 6' deep piers (every 6 feet or so). Concrete piers such as these also support the 4X6 beams (on which are laid 2X10 joists, then 3/4" ply...I think it's 9-ply raw birch...;^). The deep piers are there to keep the house anchored down, as we live on what's called expansive soil (adobe).

Anyway, the exception to this framing is the room in which I have my 2-channel system. There, on top of the 4X6's (spaced 4' on center), sits 1-1/8" T&G plywood. Unfortunately, that room is REAL bouncy. I've been considering pulling back the carpet, cutting an access hole, and getting in there with some framing material and metal angle braces I can attach to the stem wall to at least stiffen the spot where the turntable sits. There's hardly any working room under there. In the Winter (when the soil expands), there's, maybe 12" under the beams to soil. Closer than I'd like, but whaddaya gonna do?

Tomorrow I will go into detail about the wall framing in my house, then next week...THE ROOF!

[Gilbert]

There are many ways to tackle or lessen floor vibrations. One of the most popular is adding balast, the trick to adding balast is knowing where to place it, and how much. I am in no way saying that a wall mount is illogical or a useless isolation technique. Heavens no, because I have no experience with any of this. I'm only looking at the problem of TT isolation and combineing what little knowledge I know about construction.

For me, based on what I know about construction, member connections, and materials engineering (not to mention simple statics).... A stud wall mounted systems, whether attached directly to the studs, or not, would be my last choice. I have NO EXPERIENCE with any type of TT isolation systems, whether floor or wall mount. If my home were constructed on pier and wood beam foundation, my first choice would be to locate my TT as close to a load bearing wall as possible, before considering other options. Adding shoring and maybe some balast would be my second choice.

Now, following Professor Fini's 2-part lecture series on residential construction, we will have a 10min. recess, and then promptly begin with some wood composite construction vibration analysis. Bring your calculator's and some scratch pads, because vibration analysis is a very lengthy and tedious analysis..... yes I have done the analysis, but not with respect to TT performance.[]

Ciao'

[tigerwoodKhorns]

I have recently moved and have a new set of isolation challenges but I think (I have used this one in the past also) that I'm going to go with the suspended setup just above the left side of my rack behind the speakers[]

Nice speakers!