Oops... Re: Unusual rib structure?

[Delwin D Fandrich]

----- Original Message -----
From: "Sarah Fox" <sarah@gendernet.org>
To: "Pianotech" <pianotech@ptg.org>
Sent: May 07, 2003 10:32 AM
Subject: Re: Oops... Re: Unusual rib structure?


> Hi Thump,
>
> >      As you know, vibrations pass more rapidly along
> > wood grain, than across it. I believe that the intent
> > here was to allow the vibrations, passing into the
> > ribs from the bridge crossover point, to have another
> > means of surface distribution. One which helps them
> > overcome the "cross grain slow-down". And I suspect
> > that Mr.Wissner tried it for this reason, liked the
> > effect, and let it stay.
>
> Dunno...  These ties are at the ends of the ribs, not the middle.  I was
> thinking they might be under light tension to help maintain the crown.
>

They are there to simulate a real soundboard cutoff bar. They evolved from
a time when the largest possible vibrating area of soundboard was
considered to be some sacred. Indeed, it still is by some piano makers,
evidence to the contrary notwithstanding. In any case, these straps did
improve the sustain slightly through the mid-tenor and lower treble. Not as
much as a real cutoff bar would have, but they were/are better than
nothing.

Del