[CAUT] Re. Dollies and projection

[Alan McCoy]

Thanks Jim,

I appreciate your thoughts.

Alan


> From: James Ellis <claviers at nxs.net>
> Reply-To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Date: Wed, 10 May 2006 20:11:37 -0400
> To: <caut at ptg.org>
> Subject: [CAUT] Re. Dollies and projection
> 
> Alan McCoy asked if there is a consensus whether concert pianos project
> better if their legs rest solidly on the floor as opposed to being on a
> dolly with rubber-tired wheels.  It don't think there is any consensus, but
> I believe more people believe they do than believe they don't.
> 
>> From my own experience, I think other factors play a much more important
> part as far as sound projection is concerned.  I have heard pianos on
> dollies that project just fine, and others that don't.  I have heard pianos
> on hard-wheeled casters that project just fine, and others that don't.
> 
> I can see a special case involding a wooden floor supported by wooden
> beams.  The floor itself becomes a huge sounding board, and if the piano
> rests solidly on it, that might have some slight effect on the bass and
> mid-range response, but not the high treble response due to the huge mass
> of the piano itself.  But don't quote me on this because I have never
> measured it, and unless I do, it's an open question.
> 
> If a piano is placed over a plush carpet, its projection will indeed be
> compromised simply due to the sound absorption of the carpet, not because
> the carpet isolates the casters from the floor.
> 
> A same piano sitting on a concerte floor will sound vastly different from
> the way it will sound if placed over a wooden floor, whether it's on a
> dolly or not.  The reason is that the wooden floor in close proximity to,
> and parallel with, the piano's soundboard, is coupled to the soundboard by
> the air, and also vibrates a little bit - definitely enough to alter the
> tone and projection, and perhaps add a few resonant frequencies that may or
> may not be desired.
> 
> What's going on here is much more complicated than just whether or not a
> dolly under a piano changes its projection.  Everything else being equal, I
> don't think it makes much difference, provided the piano has a good, heavy,
> solid rim and rigid plate, as most high-quality concert pianos do.
> 
> Having said that, you definitely don't want a concert grand that's going to
> wiggle and bounce when the pianist really gets into it.
> 
> Jim Ellis
>