Floor material to reduce sound transmission?

[HapiCmpur]

A friend is about to inherit a grand piano (not bad, eh?) and she just emailed me to ask if there's a product she can put on the floor to reduce sound transmission to the apartment below. She recently removed the carpeting in the room that will become the piano's home, intending to replace it with Solarian tile. Now she's wondering if there's a good sound-reducing underlayment she can put down before installing the Solarian tile.

What good options, if any, does she have? If you don't think there's an underlayment that will give decent results, any other suggestions would be greatly appreciated. (Suggestions, that is, that don't involve giving you the piano.)

 

[HapiCmpur]

Anyone...anyone? Bueller?

 

[RICK FITZPATRICK]

f you don't think there's an underlayment that will give decent results, any other suggestions would be greatly appreciated.

There are products, but they're not cheap. Nor easy to install. They work by acting as a "decoupler", and are good for airborn as well as impact barriers, up to a point. However, I would tend to think that a Grand Piano would place point loads(THREE LEGS) that these products are not designed for. Specifically, I would submit that specific isolators would have to be used UNDER the point loads and engineered within the system as a whole. Here are some types. I would even suggest calling them and see what they can suggest for this problem. I bet they've done it many times.
http://www.kineticsnoise.com/arch/pdf/arch.pdf

Especially since they can do this
http://www.kineticsnoise.com/industrial/precision.html

 

[HapiCmpur]

Specifically, I would submit that specific isolators would have to be used UNDER the point loads and engineered within the system as a whole.

Hey FitZ, thanks for responding. Do you (or anybody else out there in BBS Land) have any suggestions about what to put under each piano leg? I'm aware that neoprene is often used to decouple monitors from monitor stands and guitar amps from floors, but monitors and amps don't weigh quite as much as a grand friggin' piano. I'd imagine one would need neoprene blocks the size of Volkswagens to isolate something with that much mass. Maybe I'm wrong, though.

I'm sure my friend is also going to be concerned about aesthetics since this setup is going to be in her living room, so what's likely to give her the most spot isolation for the least amount of eye-sore?

 

[RICK FITZPATRICK]

but monitors and amps don't weigh quite as much as a grand friggin' piano.

You got it. In fact, if this is a second floor, has anyone addressed the structural aspects as far as this floor or any support below, carrying these point loads, as well as the weight of the whole piano? Is this an apartment? Or home? Does anyone know anything about the structure of the floor? Let me know This is probably in the engineering sphere, and without knowing anything about the existing structure, I doubt if anyone would venture a solution guess. Under some circumstances, it would seem logical to build a lowered support with an heavy duty isolator supporting a floor level "decoupled tile", whether it is wood or tile. I know an isolator can be very small, if it is tested?calculated for the weight of the point load. But this is way out of my league as far as actual solutions go. Let us know about the room/structure/situation though. Maybe Michael will jump in here. HE is a pianist AND an engineer!! Hey MICHAEL!!!
fitZ

 

[HapiCmpur]

This is probably in the engineering sphere, and without knowing anything about the existing structure, I doubt if anyone would venture a solution guess.

That's a good point. I need to collect more info. In addition, I think there's another factor here of equal importance: She's dating my best friend, and he wants to marry her. If he persuades her, she'll be moving out of her current residence, so here's what I think I'll suggest to her under the circumstances. Please tell me if I'm off base or if there are some even better solutions that haven't occurred to me.

I'm going to recommend that for now she just install whatever finished floor will give her home the best resale value for the buck, set each piano leg on a couple of neoprene pads (like this: http://www.barrycontrols.com/defenseandindustrial/productselectionguide/data/NeoprenePadSeries.aspx), and start baking monthly pies and cakes for her downstairs neighbors.

If she plans to stay in the house a bit longer, then I'll recommend that she build a platform, sort of like a raised stage, that will accommodate the entire piano plus the pianist. The platform will be on joists outfitted with rubber decouplers (like this: http://www.soundcontrolroom.com/decoupler.htm), and the spaces between the joists will be filled with rigid fiberglass. The platform can go with her when she moves.

Does this sound like reasonable advice under the circumstances?

 

[TexRoadkill]

You could build a riser for the entire piano that is decoupled from the main floor. Using some neoprene then cinder block then a 1" marble slab would isolate the platform pretty well. Just build 6 of those (about 6"-10" high) as the riser supports and cover with frame and wood and finish too taste.

Bear in mind all of this will simply reduce mechanical transmission (vibrations) and won't actually reduce the sound transmission through walls and floor. If the building is pretty sturdy that may be enough to keep the neighbors from getting too pissed off.

Adding a double layer of plywood with overlapping seams for the subfloor before installing the tile may help with the sound transmission.

 

[RezN8]

more research needed

Rick and Tex have some good points here, but I suggest you do more research before you make any decisions. The wrong kind of platform could increase SPL in the room significantly (especially boomy freqs).

One possible solution might be a portable dance floor - like the ones they use at hotels. When your friends are finished renovating, lay down some absorbant material, like 6" compressed fiberglass or rockwool, then lay the portable dance floor on top of that. Then, of course, the piano.

This will significantly reduce the vibrations to the floor below - AND it's portable. But don't just take my word for it. Do so more research.

Best of luck, Rez

 

[HapiCmpur]

Thanks for the great suggestions, guys. And thanks, RezN8, for the caution about hollow platforms. I'll pass all this info along.