Steinway Sustain

[Tony Caught]

Hi Del

Major snips

----- Original Message -----
From: Delwin D Fandrich <pianobuilders@olynet.com>
To: <pianotech@ptg.org>
Sent: Wednesday, April 18, 2001 5:35 AM
Subject: Re: Steinway Sustain
> (At least this is what usually happens. Some piano designs are such that
> considerable distortion can be introduced in the soundboard/rib structure
as
> humidity causes the soundboard panel to swell. The relative height of the
> bridge stays about the same -- string deflection doesn't change much --
but
> that portion of the soundboard between the bridge and the inner rim bows
up.
> From the side and along the ribs the soundboard takes on a slight 'S'
curve
> shape. In these cases it is anybody's guess as to what will happen to the
> sound during periods of high humidity. Generally both power and sustain
> suffer.)
>
As I understand, it when the piano is strung, any area where down bearing is
increased, could not be picked up by measuring the down bearing over the
area as the whole bridge (which is stiff) is levelling the down bearing to
an even point.
The problem could still exist an be undetected .
>
> This is a common problem with pianos using compression-crowned
soundboards.
> For a variety of reasons -- refer back to the articles I wrote for the
> Journal for a more complete explanation -- soundboard crown dissipates
more
> quickly through this critical region than it does through the other parts
of
> the board. Since there are also a couple of other common design flaws
> through this region (in addition to the method of obtaining soundboard
> crown) the result is the very typical loss of sustain -- hence our
reference
> to this region as the 'killer octave' -- you have found with this piano.

You are confirming my opinion that the 'killer octave' is caused by other
than the action it total and that the problem has to be addressed in other
areas first. As you point out, the soundboard is the problem or the string
to soundboard area is the problem.
Possible causes, aliquot bar to low, string contact with bridge, bridge
weakened at this area, bridge soundboard contact not solid, rib or ribs weak
in affected area, soundboard thinned in affected area, soundboard distorted.
>
> You can sometimes make the problem less bad by all of the regulating and
> voicing techniques offered by other posts on this subject, but the real
> problem lies with the soundboard and until that is dealt with none of the
> other repairs will be all that helpful.
>
>
> You can also sometimes make the problem less bad by adding some weight to
> the bottom of the soundboard along the bridge line. While this is not as
> effective as replacing the soundboard with one having the proper amount of
> stiffness, it may help. Adding mass will increase the soundboard impedance
> somewhat more with the higher partials which you don't really need, but it
> will also have some effect on the fundamental frequencies involved through
> the killer octave region. Start with about 100 grams located as close to
the
> center of the worst area and go from there.
>
Will try the weight idea first to see if it will improve the sustain/tone of
this area and if so, what is your opinion in thickening the ribs in the
affected area or in stiffing the ribs. would this do the same thing as
hanging a weight ?

>
> Then Kevin wrote: ..... NO! TONY WROTE
>
> > Remember what Del said about soundboards. Today they are all made too
> thick
> > (not shaped in the bass), makes the board stiffer, requires
harder/heavier
> > hammers to excite the strings, lots of volume but no sustain.
>
> In general this is true. However, soundboards can also be made regionally
> too thin. This is especially in the upper tenor and treble. And even more
> especially if these boards are compression-crowned. Excessively thin
> compression-crowned soundboards have a habit of de-crowning themselves
very
> rapidly even without being exposed to high humidity climates.
>
>
>
> > wouldn't mind
> > betting that if you cut the soundboard clear of the rim in several
> sections
> > (as Ron Overs did in the Yamaha G2 in one section) then put Abel hammers
> on
> > you could have a decent sounding piano.
>
> We've been doing this regularly on a variety of different pianos for some
> years and now have a considerable backlog of experience with the
technique.
> (It was also standard along the bass of our U122 upright.) It won't help
> through the killer octave region however. Here the problem is already a
loss
> of stiffness and cutting the soundboard free would only reduce the
stiffness
> further.

Del this was in reference to another problem Kevin menioned in relation to a
Asian  piano that had one hammer that was all attack, no sustain. Just my
thoughts on inproving the tone on some Asian pianos in general.

> Regards,
>
> Del
>
Regards

Tony