Stein grand unique board

[Phillip L Ford]

On Sat, 5 Jan 2002 09:10:42   
 Delwin D Fandrich wrote:
>
>----- Original Message -----
>From: "Phillip L Ford" <fordpiano@lycos.com>
>To: <pianotech@ptg.org>
>Sent: January 04, 2002 9:02 PM
>Subject: Re: Stein grand unique board
>
>
>> So all the waves are travelling in those little ribs?
>>
>> Phil F
>
>
>
>The soundboard assembly is a working system. You can't isolate out some
>certain part of it and say it's working alone.
>
>Del
>
I was just trying to rib Ron.

I believe I understand that the assembly works as a whole rather than in parts.
But I'm trying to understand the function that the parts play in the whole.  I
don't doubt that there are waves traveling in the board and ribs (even though
I claimed I was sceptical).  But I question whether having them reflect back
from the rim is necessary for the soundboard to serve its function in the assembly
or whether this wave traveling and reflection is really the thing that we need to
worry about in designing a soundboard system.  If you can separate the soundboard
completely from the rim (I realize that the Stein was not completely disconnected)
and have it still function properly in the assembly, then perhaps the conventional
idea that the rim needs to be heavy to 'reflect waves' is not correct.
Or perhaps the idea that the rim needs to be heavy is correct but
for a different reason.  One way to design would be to do as Ron N suggested.  Make
the rim heavy so that you essentially have an inert attachment for the soundboard.
We know this works, and can work well.  It also eliminates one of the variables that
you have to worry about.
But, as you say, the assembly works as a whole.  Perhaps the rim should be one of
the variables.  Perhaps if you had a really thin rim, or a solid rim with a knife edge
sitting on top of it that the soundboard is sitting on which allows it to act as a simply
supported member, or some other idea I haven't thought of yet you might get a sound
that is more to your liking.  Since the assembly works as a whole, chances are if you
use one of these other rim designs you will have to change your board design, and rib
design, and bridge design and you'll be giving up the opportunity to use a couple
hundred years of accumulated wisdom but you might have some fun in the process.

Phil F