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I am trying to get a set of 4
"Jansen Caster Cups" for my up coming upright Piano.
http://cosmomusic.ca/caster-cups-upright-clear.html
They will be sitting on top of a carpet, for decoupling vibration (for downstairs).

Floor is made of 200mm thick concrete.

Any ideas about these? they are more expensive than I thought.

Do these caster cups have any particular acoustic de-coupling qualities/features? It is not my impression they do.

they just serve the purpose of increase the area of contact...to spread out the weight to the carpet...
or i may just get some stone wool pad instead from dollar store...

Jurgen Goering has what you need. He sold a set to me for my piano. Work just fine.

Google "piattino caster cups" if de-coupling is what you are looking for.

Cheers!

I ordered some neoprene sheet. I am pretty sure these are the best material for decoupling.
Piattino caster cups seem like great idea& design but right now $200 on caster cups are way over my budget. I think I can achieve same result with some DIY work.

I think you need to be realistic with your expectations of neoprene sheet. In order to have any chance of creating a cushion for such substantial vibrations, you need a considerable mass in your rubber insulator. I don't think a neoprene sheet would do much at all because it's too thin. When the weight of the piano is on it, it will compress to the extent that it's almost a solid substance like the floor under it. Despite their size, casters concentrate the mass on a very small contact area. To have any chance of decoupling the piano from the floor, you need very thick and reasonably wide blocks of rubber and large cups for the casters to spread the contact area of the piano's mass. This creates an intermediate zone between the piano and the floor and allows a certain amount of vibrational energy to be dissipated in the rubber material. Even then, the enormous weight of a piano will compress any caster cup to a fair degree and you are still going to get transmission of vibration to the floor.

It's a question of how far you want to go - at some point the law of diminishing returns with kick it. But generally the wider and thicker an insulator is, the more effective it is. Neoprene sheet is neither thick not wide in this context - unless you have found some particularly thick neoprene and you are going to make a caster cup to sit on top of it with a large surface area. I'd say the Jansens are a better solution when all is said and done - much neater.

Thanks Ando, I have also ordered some FLOR rug tiles they will be sit on top of the neoprene - so the neoprene sheet will more work like underlayment.
the backing of carpet rug is made of vinyl composite.

I am planning to get 4 large caster cups (maybe Jansen or something cheaper) to spread out the weights.

plus theres already a very good underlayment underneath my laminate floor, with they are with high FIIC, around 55 to 60 i think (Field Impact Insulation Class) rating.

I think the result will be decent to stop the impact sound transfer to downstairs.



neoprene only works as a decoupler instead of absorber.
the graph shows a redicilously high 91 IIC (which is very close to my setting)

in terms of airborne sound, im planning to get 6 inch thick minearl wool insulation at 2.5 lb/sqft3. i know at 4 inches thickness they have an NRC rating of 1.00 at 125hz. they will cover up the back of piano.


any comments are appreciated.

Steven

I see Steven, you have more going on there than I originally assumed. I think with a floating floor with underlay, the neoprene, the carpet tiles, and the caster cups, you have done pretty much everything you can on a budget. Having multiple layers like that with soft materials in a sandwich configuration should reduce the problem to an acceptable level. Let us know how it turns out.

Incidentally, I inserted thick acoustical foam (around 5") into between the posts of the back of my piano. Not touching the soundboard, but blocking the rear exit of sound. It works to a large extent. Much more manageable in a quite lively room with timber floors. On a subjective level, I'd say it sounds like it's almost half as loud as before.

Thanks again Ando for supporting my thought. Are you familiar with Jansen cups? Are they solid and flat at the bottom?

or a hollowed bottom like this (which i think defeat the purpose of increasing contact surface)

[img]http://cdn3.image-tmart.com/prodimg...-Triangle-Piano_2_320x320.jpg?1331023715[/img]

Yes, the Jansens (and any decent cup IMO) are flat bottomed.

Thanks. I have just ordered four.

Embarrassingly low-tech, but I cut out circles of moving blanket to match the size of the caster cups, and put one between each cup and the hardwood floor. Maybe it decouples, maybe not, but can't hurt I guess. Plus, you can shove the piano around a bit, because the blanket circles glide on the hardwood.

I did a little looking around on acoustics/soundproofing sites and found that the commercial products used to float floors are made of 60 durometer EPDM synthetic rubber. I would forego all the guessing with combinations of neoprene (too soft) and packing blanket (ditto) and glue some of this to the caster cups--the thicker the better. Another product to look at is Mass Loaded Vinyl. Two lb weight is 1/4 inch thick. Both products can be found easily on the internet and can be cut with a razor knife. The trick will be finding someone to sell you small amounts.

Wait, has it been established there's a problem with transmission through the concrete floor?

Kurt

I have the Piattino caster cups that Jurgen Goering is selling.

They look good, and together with a thick rug and carpeted rooms, more or less decouples your piano from the floor below.

That said, they won't stop sound from going to your neighbours. For that, I got acoustic foam soundproofing from Edwards Strings Covers, and a thick piano cover. The sound dampening is not exactly even across the entire range, but it's good enough.

So far no complaints from neighbours (db level is now around 75dbs or so, or like a stereo), but I haven't played late at night that much. I take the sound proofing out when I have parties or playing for friends.

Rich,

Where can those be purchased? Just bought one of the Cunningham Uprights from Peter yesterday! Researching ways to lower volume a little if it becomes an issue in our townhouse. Good thing is we only have neighbors on the sides of us and not underneath.

Alex

Here's a link to the Piattino Caster Cups sold by Jurgen:

http://www.pianofortesupply.com/accessories/caster-cups/piattino/piattino-acoustic-caster-cups-2/

Thanks for the plug Marty.
I have created a new page for Piattino Caster Cups on my piano tuning website here:
Piattino Caster Cups

They really help. Here is a recent assessment by a client:
Piattino test

Hi, I'm moving to a new apartment in a week, and frankly, as beautiful as the Piattino cups are, they're out of our budget right now. I was, however, able to find an internet site that will sell 2Lb Mass Loaded Vinyl by the foot. If I were to cut and layer the material under my caster cups, will that be similarly effective at dampening? It's a concrete building with all masonry interior partitions and floors/ceilings. But still, it's the first time we've had a piano in an apartment and want to be as careful and courteous to others as possible.