Soundboard backposts ??

[Richard Brekne]

Del... As usual you are up to your informative best.. many thanks indeed. I had
no idea that anything like this had ever been serioiusly considered. Food for
thought as far as it goes.

I am wondering about one thing tho.. You mention that solid posts would mean
that the strings would be required to move the back posts (beams) as well as the
sound board to produce any energy (sound). Just how big an effect would a few
square inches over the whole of the soundboard have ?? Wouldnt the rest of the
board be free to vibrate.... and wouldnt energy take the path of least
resistance ??

These are at least the jist of the arguments presented to me by my counterpart
in this discussion we had, (are still having..grin) And I am not informed...well
enough read, nor experienced to authoritivly counter these. If you have the
time... grin..

Thanks again Del..

Richard Brekne
I.C.P.T.G.  N.P.T.F.
Grin.. Now Head Technician for the University of Bergen (patting myself on the
shoulder a bit)
Bergen, Norway



Delwin D Fandrich wrote:

> ----- Original Message -----
> From: Richard Brekne <richardb@c2i.net>
> To: <pianotech@ptg.org>
> Sent: Wednesday, December 01, 1999 2:04 PM
> Subject: Soundboard backposts ??
>
> > Hi list..
> >
> > Got into a discussion today with another piano tech which prompted me to
> > put the following question to you experts out there.
> >
> > Given an old beater with a flat soundboard, perhaps a bit of negative
> > crown... What would the effect be of glueing in wood pieces between the
> > ribs and the back frame beams to force and hold the soundboard into a
> > artificial crown ??
> >
> > sounds off the wall, I know... but I am curious to hear your responses.
> >
> > Richard Brekne
> > I.C.P.T.G.  N.P.T.F.
> > Bergen, Norway
>
> -------------------------------------------------------------------------
>
> Richard,
>
> Crown, by itself, is not the issue.  It is the relationship between the
> strings and the soundboard.  To function as a transducer, the soundboard
> must be able to move in response to the vibrating energy in the string.
> Putting a solid coupler between the backpost and the soundboard would
> (could) force a curve into the soundboard, but I'd hardly call it crown.
> Now the string will have to move both the soundboard and the backpost to
> create any sound energy.  Backposts are often fairly difficult to move.
>
> Garold Beyer has replied with a reference to the old practice of installing
> springs between the backposts and the soundboard at strategic spots.  This
> was a bit of a fad back in the mid 1960's and the early 1970's.  Several
> rebuilders, myself included, had been experimenting with this notion from
> time to time.  I installed these devices -- the best were 1957 Corvette
> progressively wound valve springs -- on several old upright and grand pianos
> with varying degrees of success.  (Actually, there was nothing magic about
> 1957 Corvette valve springs.  I had owned one and at one time had replaced
> the heads.  I had a few of the old springs floating around.)
>
> The practice was eventually ridiculed out of existence by the more
> traditional and more "respected" members of the trade as being a
> non-professional repair, but I have come back to the idea several times over
> the years.  I guess I am non-professional enough to wonder just what the
> dynamics of the process are.  And to not worry overly much about what
> tradition thinks of some of my strange ideas.  Were I doing the same type of
> rebuilding today that I did then I would probably still be experimenting
> with them.
>
> As for not being "professional," well, I put soundboard springs into the
> same category as all of the CA pinblock repairs I read about.  And the same
> principle applies: Yes, the piano needs a new pinblock (soundboard), but for
> a nominal amount of money -- compared to a new pinblock (soundboard) -- this
> repair will effect some improvement and possibly postpone the inevitable for
> a few more years.  It will not tune (sound) as well (good) as a properly
> remanufactured instrument, but it will be better than it was. And for a lot
> less money.
>
> Regards,
>
> Del
> Delwin D Fandrich
> Piano Designer & Builder
> Hoquiam, Washington  USA
> E.mail:  pianobuilders@olynet.com
> Web Site:  http://pianobuilders.olynet.com/