what is downbearing?

[David Skolnik]

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Julia -

The questions are disarmingly innocent when viewed within the context of 
the numerous debates, at times extremely contentious, which have taken 
place here over the last x number of  days, weeks, months, years.  In other 
words, you are absolutely correct in asking, but simple answers do not do 
your questions justice, if you truly wish to understand.  In Dale's effort 
to supply just such a simple answer, there is, mixed together, both 
accurate and potentially confusing information...confusing in the sense 
that it states as accepted fact much of what we seem to have been arguing 
about, of late.

I do agree with the basic idea of downbearing as being the force directed 
against the bridge in response to a deflection of the string plane by the 
bridge height, and, I suppose it is the general consensus that   "It is 
important there be some, just how"much" would vary with the specific design 
of the piano."   I also agree that both the archives and past issues of the 
journal should be thoroughly examined in order to begin to understand the 
larger ramifications of downbearing.

However, much of the remainder continues to be debated:

>It is also important that there be "crown" on the soundboard.

So what do we do with all these claims regarding pianos that seem to sound 
good without any measurable crown?

>If the soundboard has collaspsed--it is still possible if the plate is low 
>enough that there will be "downbearing".

But we still debate whether such downbearing has the same effect as the 
same amount on a flat or positively crowned board.

>With negative downbearing the strings will not touch the top of the bridge.

Of course, Dale means that, were you to remove the bridge pins from a 
string which had such negative downbearing, it would not contact the bridge 
surface.  Yet negative downbearing is another of those issues whose 
significance has recently been undergoing review in this forum.

>Postive crown and positive downbearing are usually considered to be 
>desireable for an instrument to sound well.

And yet, as stated above, there are constant claims of fine results without 
the presence of crown, for example:

>Date: Wed, 31 Dec 2003 20:56:42 -0500 (EST)
>From: Erwinspiano@aol.com
>Subject: Re: No downbearing ?
>I recently put bridge caps on one of the first Baldwin Uprights (1880) 
>ever built. (Gorgeous looking & sounding) The board was flat as a pancake. 
>I shimmed hairline cracks and then applied scraped off the old varnish and 
>epoxy finish treatment to the front of the board. This is an amazing 
>sounding piano. I really think that the hardness of the epoxy finish is 
>also a contributing tonal factor.



I'm not looking for answers to the above comments here, as I'm still 
slogging through the many posts that were submitted, just since August, 
regarding downbearing, crown and soundboards.   As much as I felt 
unfulfilled by the recent threads regarding downbearing and coupling, I 
realize that any current discussion must be informed by what others have, 
with considerable sacrifice and generosity, already contributed.

Good luck in your quest, Julia.

David Skolnik




At 11:44 AM 2/19/2004 -0500, you wrote:
>              Hi Julia
>    The list just had quite a discussion on it 2 weeks ago. Check archives.
>
>         Regards--Dale
>Hi Julia,
>
>Downbearing is the force the strings on a grand piano apply to the bridge.
>Hence the name "downbearing". It is important there be some, just how
>"much" would vary with the specific design of the piano. It is also
>important that there be "crown" on the soundboard. If the soundboard has
>collaspsed--it is still possible if the plate is low enough that there will
>be "downbearing".
>
>With negative downbearing the strings will not touch the top of the bridge.
>
>Postive crown and positive downbearing are usually considered to be
>desireable for an instrument to sound well.
>
>
>At 11:11 AM 2/19/2004 EST, you wrote:
> >Greetings,
> >
> >           What exactly is downbearing? Does it affect the sound of the
> >piano or is it a mechanical/ physics measurement for the playability of the
> >piano? Why is it important to measure it? Can it be calculated by a
> >formula(e)? What does it mean?
> >

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