Baldwin SD-10

[Delwin D Fandrich]

----- Original Message -----
From: "Ron Nossaman" <RNossaman@KSCABLE.com>
To: <pianotech@ptg.org>
Sent: September 06, 2001 7:08 AM
Subject: Re: Baldwin SD-10


> > By making the
> >notch deeper than the rib will ever be there is no need to 'fit'
anything.
> >And, as you point out, neither is there any acoustical need to do so.
> >Acoustically the damage is done when the rib crosses over the edge of the
> >inner rim anyway. And this way Marketing can claim notched-in ribs
without
> >forcing the factory workers to waste much time on the process. It works.
> >
> >Del
>
> It always has for me. Where I was eventually going with this was that
these
> "design quirks" are manufacturing expedients, rather than some sort of
> performance voodoo. I've always heard how absolutely critical an absolute
> rib fit in the rim mortices is, but haven't found it to be even remotely
so
> from a performance standpoint. Unless, that is, the mortice is too small
> for the rib end to fit into, or the rib moved on me when I clamped it to
> the board and doesn't exactly match the mortice location any more. That
has
> some negative effect on the efficiency of my performance as installer. But
> that never happens, does it?
----------------------------------------------------------

No. And posts like this should be banned from the list. How do you expect
the piano industry to survive if you take away the right of the
manufacturers and/or dealers to confuse the public into buying their pianos.

Seriously, I've only encountered a very few pianos that have had their ribs
'properly' fit to the inner rim. It rarely happened back in the good ol'
days and it even more rarely happens today. This whole practice is a
carryover from the animal hide glue days and is done today more out of
tradition than anything else. The idea was that the end of the rib should be
physically supported and 'clamped' between the bottom of the rib notch and
the bottom of the soundboard, thereby reducing the stress on the glue joint.

Unfortunately, through most parts of the scale the practice actually works
against the freedom of motion required by the soundboard for best acoustical
response. In most pianos a reasonable argument can be made for insetting the
top few ribs to stiffen things up a bit. (An even better argument can be
made for better soundboard and rib design.) Through the bass region the
practice is not only unnecessary but is counter-productive.

In addition, in high-production piano manufacturing the practice can lead to
very real problems if either the notches are cut too shallow or the rib
feathering is not cut thin enough. Some time back I examined a number of
pianos by one manufacturer in which the soundboard itself was held about 1
to 2 mm off the surface of the inner rim because the overly thick ribs
bottomed out on the notch and prevented contact. They sold them anyway, I
think. Shouldn't matter, right?

Del