Hanging/suspended TT

[rplace]

In my original post a while back Original Thread you guys had a lot of helpful info. Two mentioned suspending the TT form the ceiling. That is exactly what I did inside the equipment closet (see original post for closet pix, scroll down a bit). Not so much to prevent vibration of floors, but because I needed the TT close to the equipment, I needed the space under the stairs for growing record collection, I cold not put the TT in my rack as it was too wide and a shelf like Larry C suggested would put the TT sideways and make queuing up the LP difficult on the side wall or too far into the closet to reach if on the back wall. At least for now the suspended TT seems the best optionbut I am still open to suggestions.

Ill try and get some pix this weekend, but basically I have a shelf narrower then the plinth front to back and wider then the plinth side to side. The shelf hits all four feet of the TT but allows the front to hang over shelf just a bit. This is great because the power switch of my MMF-5 is on the bottom left/front of the plinth.

I suspended the shelf with stainless steel aircraft wire and put a turnbuckle on each wire to aid in leveling it. After 3 day of listening I am pretty happy with the setup.

My questions are:

Should I have any concerns with a suspended shelf for my TT, are there any special issues I should be aware of?

Currently the shelf is cheap pine, dont you want some mass for the base of a TT? Should I look into using my pine shelf as a template and having a final version made from Granite or Marble?

Thanks for all the TT and vinyl help to date, Rich

[ben.]

Rich,

Sounds like a nice setup. If suspending granite or marble, be wary of their resonance. You'll need to use a pretty thick piece to avoid the problem. I was using a nice piece of granite, which I placed on four rubber stoppers for feet. Looked super, but my Scout really lacked bass extension that way. The granite really rang badly when I tapped it, too. I applied some asphalt-based damping material to the bottom, which helped only slightly.

What ended up fixing the problem was laying a spare wooden shelf from my cabinet underneath the granite. Footfalls are back, but that's an issue that shouldn't be too hard to solve (sorbothane feet under the board, I think).

Keep in mind my 24"x 19"x roughly 1" piece of granite weighs about 80 lbs, too. I would probably go 3" thick if I were relying on the mass of the stone by itself.

[rplace]

Thanks for the quick reply, Ben. I am confused now. I was under the impression that you put some big honking piece of something under a TT to provide mass which in turn absorbed any vibration. Am I wrong here? Are you saying that the granite you used actually vibrated/resonated and hurt the bass? Do you know how/why the wooden shelf corrected the problem? Also what does the term footfalls mean?

Thanks, Rich

FYI, my current wood shelf is 11.5 X 20. This gives me just enough side to suspend the shelf with out interfering with the plinth. But almost gives the illusion that the TT is floating in mid air. Well except for the four wires hanging down from the ceiling. Not too worried about the weight as the stainless steel aircraft wire is good to 900 pounds per strand. Now the mounting to the floor joists might be an issue as weight increases, but I can over engineer that with a little more effort.

[fini]

Rich,

The term "footfall" refers to footsteps in the room being picked up by your system, notably the vinyl rig, and being heard through your speakers.

Hey, got any pictures of the suspended shelf?

[ben.]

Fini covered the footfall issue.

Adding mass is not always best. Some TTs actually do better with a light mounting scheme, I've heard. Also, there's lots of variables. Mass doesn't automatically equate to resonance control, as I found with the granite. The homogenous nature of the stone is a problem, as it leads to these resonances, as the material vibrates sympathetically. It seems like better results are achieved with two or three contrasting materials. In my setup, the granite adds overall mass, and rigidity for the Scout's cone feet to drain vibrations into. The wood under the granite serves to damp the resonances inherent in the granite. The difference is not subtle. Before the wood underneath, resolution and clarity was fine, but the bass was really nonexistent.

I would say that if you are happy with the tonal balance, leave it be. Unless the cheap pine bothers you, that is. The fact that you don't really see it factors in, too.

[Jimmy James]

I have my table set up in a similar way. I have a store bought shelf from Home Depot that I attached two hinges to the edge. Then I attached the two hinges other halves to the wall studs with some rubber inbetween the wall and the hinges. At this point it's kind of like a Murphy bed. Then I attached two eyelets to the forward side edges of the shelf and two hooks on the wall. I suspended the self at the correct level position with stainless deep sea fishing cables and hardware. The hardware only touches the eyelets at a very tiny point. They are the heavy steel clasp things you use for quick disconnect when you go deep sea fishing. It's kind of a hybrid between your design and a rigid wall platform. I thought about doing it your way but I didn't want it to be able to sway, so I came up with this compromise. I didn't have a closet to use where everything could be safe. I'm no engineer but I think the wires transfer a lot of the unwanted energy away from the shelf and table like a guitar string where it goes to the hooks attached to the studs. The rubber behind the hinge halves helps keep any wall resonance out. I have been very happy with this homemade platform. You can stand right in front of the table and jump up and down as hard as you want and it doesn't hurt a thing. I am working on a better way to attach the hinges and it may work even better. Everthing seems to sound like it should so I'm happy.

[fini]

Ben,

What do you think about a granite/sorbothane sandwich (where the granite is the bread, and the sorbothane is the meatloaf)? Bolted together, and suspended from the ceiling. Tom Longo's cat would look spiffy on it anyway.

[Jimmy James]

I almost forgot. I have all of this rig a few inches above the top of my equipment rack. When I'm not using the table I can put some homemade rubber and foam blocks under the front edge of the shelf to take the tension off the wires and help keep them from stretching over time or maybe worse. That's what also kind of worried me with the floating design, how to support it when I wasn't using it, not counting that mine was easier for a lazy guy like me to do. I found two wall studs right where I needed them. The ceiling would have been a heck of a lot harder for me anyway! Someday I'd like to try it your way.

[ben.]

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On 5/27/2005 11:49:28 AM fini wrote:

Ben,

What do you think about a granite/sorbothane sandwich (where the granite is the bread, and the sorbothane is the meatloaf)? Bolted together, and suspended from the ceiling. Tom Longo's cat would look spiffy on it anyway.

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I think it'd probably work quite well. Bolting the sandwich together probably wouldn't be necessary, though, and could interfere with the absorptive qualitites of the sorbothane. I'm probably splitting hairs, though.

Something cheaper than sorbo would probably work about as well in that application.

[colterphoto1]

there is a poster here who has a wall mounted shelf with tennis balls acting as the sorbothane, then a massive shelf, then turntable.

I remember a dance club I once installed a PA, country bar, they wanted a stage coach for DJ rig. Problem was it was super rickety. We suspended a table from the ceiling, through roof of stage coach, then a layer of BRICKS, then DJ turntable rig. The combination of suspension and mass was just right.

Experiment.

Michael

[LarryC]

Rich,

I look forward to the pics! It would be nice to see pics of the others' solutions, too.

Intuitively, I myself am an "air-bladder" fan more than of heavy rock (stone, not non-classical) by itself. I have a Townshend sink, which has internal air bladders and GaryMD has one on long-term loan; these do very well at absorbing vibrations, resonance and footfalls. Bass loss is not a problem.

Joessportster has a much more economical design using gorgeous green tennis balls and a stone slab, and I suspect the tennis balls are the chief operators there. See Joe's thread, test (he has an earlier thread I can't find) for pics of his setup and jt1stcav's brother's gorgeous yellow tennis-ball setup which doesn't appear to use a slab. Anyway, Joe seems to be very happy with his setup.

I agree with the comment above that if it sounds great to you, why change anything? However, if you feel the sound is a little more gritty or bass-thin than it should be, you might slap together a tennis-ball setup and see what you think.

Sorry you can't put your TT, LPs and volume control (or even two of the three) in the same place. I'd hoped the under-stairs space and a Niles switchbox would do that for you.

Larry

[Colin]

read this and the Stereophile review, then add one racquet ball per 20 pounds of weight (including the TT):

http://www.gingkoaudio.com/technical.html

[ben.]

The trouble with stone and tennis ball-type solutions would be just what I ran into. Other TTs might not react quite like mine did to the ringing, but the granite really needed something to damp it. I think the feet/tennis ball approach is viable for isolation from extraneous structural vibration, but I can't see it helping what I ran into.

The granite is not exactly a perfect material for the application without some help, at least in the thickness I have. Looks purty, though.

[rplace]

Unless I am way off base here I can't imagine having any vibration issues from foot traffic. I am in the basement on a concrete slab with poured concrete wall around me. Add to that the fact that the TT is not on any wall or floor.

The only problem I could see would be that my wires suspending the TT are in the first floor, floor joists. If somebody was to jump up and down in my living room that might transmit down. Wouldn't the wires absorb most of that? No walls related to the khorns are involved either.

Am I underestimating the tenacity of vibrations or am I worrying about something that does not exit?

[Jimmy James]

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On 5/27/2005 3:58:26 PM rplace wrote:

Unless I am way off base here I can't imagine having any vibration issues from foot traffic. I am in the basement on a concrete slab with poured concrete wall around me. Add to that the fact that the TT is not on any wall or floor.

The only problem I could see would be that my wires suspending the TT are in the first floor, floor joists. If somebody was to jump up and down in my living room that might transmit down. Wouldn't the wires absorb most of that? No walls related to the khorns are involved either.

Am I underestimating the tenacity of vibrations or am I worrying about something that does not exit?

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I wish I could have a room with all that concrete! I don't think anything's better for resonance control or even elimination!

You said your table's isolated, in a closet? That would pretty much take care or air-borne induced problems I would think. Sounds damn near perfect to me. If you're worried about vibration transmission via the wires, get some of the stuff they put under the strings on a violin where they touch the bridge and put a little where your wires come in contact with whatever you have them attached to. The wires would work just like the strings on the instrument and get rid of any energy coming down from above, it would never reach your table. Hell, you could even tune them to cancel out any unwanted frequencies, if there were any to begin with.

[ben.]

Those wires would transmit more energy than they absorb, but probably wouldn't an issue unless you've got teenage boys upstairs.

Like I said, if I were you, I'd probably stick with what's working right now. Many of the comments above were really general in nature, rather than specific recommendations for you.

I think that the poor performance of the granite in my case was really mechanical system resonance (rather than airborne vibration) working against the needle in the groove at certain frequencies and their harmonics. I tried it at both high and low SPLs, and the results were poor regardless.

[Colin]

read the part about isolation if you do have a problem with footfalls from above...

[fini]

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On 5/27/2005 3:00:46 PM ben. wrote:

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On 5/27/2005 11:49:28 AM fini wrote:

Ben,

What do you think about a granite/sorbothane sandwich (where the granite is the bread, and the sorbothane is the meatloaf)? Bolted together, and suspended from the ceiling. Tom Longo's cat would look spiffy on it anyway.

----------------

I think it'd probably work quite well. Bolting the sandwich together probably wouldn't be necessary, though, and could interfere with the absorptive qualitites of the sorbothane. I'm probably splitting hairs, though.

Something cheaper than sorbo would probably work about as well in that application.

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I was thinking one could use a quad of eye bolts, to connect the sandwich, and to provide connecting rings (for the rope/chain/vine). Wasn't really thinking of squeezing too hard.

[ben.]

Makes sense. How about some hot glue for gravy?

[ben.]

Here's an inadverdent pic...