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Hey Frank,

Hope you've rested up from your grueling whirlwind NAMM trip.

I've personally heard several Kawai's MPAs say the same thing that Jurgen just said regarding the "grounding effects." No rubber casters, no caster cups for stage and/or performing.

Best,

Bear

Brings up another question. If rubber tracks have a detrimental effect on onstage sound, why do the NY Steinway C&A instruments have them?

Thanks Bear, it was a great trip.

I'm still not convinced about the "grounding effects" though. Sounds more psychological than factual to me. I'm guessing a 1500lb piano is already pretty well grounded, and most of the sound projection is via the soundboard. Yes/no?

Personally I would very much doubt that companies building world class pianos like Hamburg Steinways and Sauters do would dare to impede the sound of their pianos by anything, least of all a caster.

In fact, the alternative putting these ugly stage trucks underneath concert grands appears to be far less attractive to me.

In case of doubt or disagreement, anybody can always shout at the pianist during a concert:

"Hey man, take your rubber off!!"

Norbert

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Just going by what the "Kawai MPA Pros" told me. I don't have any proof one way or the other. The last time I observed an MPA doing his thing was several years ago in Atlanta while he was prepping an EX for a concert. Those amazing technicians seem to be able to hear a pin drop in the middle of a thunder storm or a hail storm. Anyway, I asked about the casters and he stated that the solid brass casters should be directly on the stage unhindered by caster cups or piano dollies, {piano trucks} or anything else for optimum sound/tone projection. That's pretty close to what Jurgen stated I think.

Cordially,

Bear

Pretty big piano, Frank, that is 1-1/2 times the weight of an S&S D !

Yes, most of the sound projecton is via the soundboard. Which means there is a residual amount that stems from elsewhere.

I am not sure about scientific studies to "prove" this, but there is plenty of "soft" evidence.

For one thing, it is well known that the stage can act as a type of secondary sounding board, enhancing the piano sound and projection in a hall.

A good friend of mine is a master piano technician in a major cultural center in Germany, where he does a lot of piano work for the German Broadcasting Corporation. They do a lot of concerts featuring the highest caliber of international pianists, recording for radio and Deutsche Gramaphone, as well as live radio concert broadcasts. All of the pianos there, including the 12 Hamburg Ds, have these casters. He said when North American pianists come, they are thrilled to play on these pianos. There is no bouncing or springiness that you have when plaing pianos mounted on a truck or spider dolly.

Insitutional piano dollies have lots of rubber surface area on the ground. I can't imagine a rubberized caster not disintegrating after a few rolls around the stage.

An institutional studio upright (the oak ones for example) have double rubber wheels all around (4) and the pianos probably don't weigh more than 400 or 500 lbs.

Imagine rubber double wheels on a grand and you only get three sets (3 points of contact instead of 4 on a vertical) and as much as four times the weight.

It would be like putting tricycle tires on a Hummer.

And what Supply said.

Thanks for sharing what you can't imagine...

Fact is, this rubberized coating is a high tech PUR substance that is baked onto the brass wheels for several hours at high temperature (vulcanized). This material has years of proven track record, among other places is said institution, rolling on and off stages, into elevators and down the halls of the piano vaults in the basement of the broadcasting station.

Supply: I wasn't disputing your vulcanized rubber-coated brass wheel at all. If you took it that way I didn't mean it. I was referring to all-rubber wheels like you find in institutional uprights or on cheap appliance dollies (as opposed to the better quality rubber and bearings on piano dollies).

Ah, but the Mason & Hamlin CC is 1400lbs (according to the 12th edition of the Pierce Piano Atlas), so with the bench ... :-)

I would agree a piano firmly planted on the floor would be more stable than one on a truck or spider dolly.
My skepticism is with rubber versus brass casters.

Of course at my playing skill level, it could be mounted on silly putty and not make a difference.

Just for fun, a dealer once demonstrated to me the quality of Bosendorfer casters. He had an Imperial on the floor of his workshop, which had a glass-smooth concrete floor.

He gave the Imperial a slight nudge and off it went like a curling stone on ice. It just moved along at a snails pace. I figured it was getting its momentum from the movement of the planet, like a pendulum. It might have moved all the way to the wall had we not both stood in front of it and stopped it.

That was the day I realized that casters lock for a reason.