buzzing on piano

[David Lawson]

Try the lock!
----- Original Message ----- 
From: "Tom & Sharla Zasadny" <zasadny at hotmail.com>
To: <pianotech at ptg.org>
Sent: Sunday, February 04, 2007 4:13 PM
Subject: buzzing on piano


> Greetings,
> What would be the origin of a buzz on this 1930's Steinway Model "M"  that
> seems
> to be soundboard related and acts like lthis:  It has been present for a
> couple of
> years; less in the summer and more in the winter and at F5only.  It is
more
> wooden
> than metallilc in quality and is more pronounced with a harder key blow.
E5
> was
> pitched up to the F5 pitch and caused the same buzz.  F#5 was tuned down
to
> F5
> and also caused the buzz.  Pressure over the bridge, movement of the
duplex,
> movement of the strings under the capo, pressure over all ribs and over
the
> soundboard top and bottom, tapping the bridge pin down and increasing its
> angle
> availed nothing. The soundboard has no cracks and bearing is good with
good
> sustain.  Visual examination with light and mirror under the plate showed
> nothing.
> High air pressure through every opening was not productive as well.
> Muting two
> strings at the F5  quieted the buzz.  When only one was muted, it returned
> though less
> than with three singing strings.  If I struck two singing strings, the
buzz
> equalled that of
> three strings with a less forceful blow.  Now here is the only diagnostic
> clue I can
> give.  When the plate bolts were tigtened the buzz disappeared though for
> only 15
> minutes.  (It came back as I was doing some regulation testing.)  I
> tightened the bolts
> again and it was quieted for a short time. Tightening again (I put overly
> heavy torque
> on this last time) lessened the buzz at F5 but it turned up at C6.   Soon
> the buzz
> became strong at C6 and remained small at F5.  I checked for glue along
the
> entire
> inner rim at the soundboard junction and I eliminated all action and
> environmental
> sympathetic vibration questions. What is this?  How do I fix it?  The
> customer is
> piano professor and accomplished performer.  He is ready for this to be
> history.
>
> Thank you friends,
>
> Thomas N Zasadny
> (home)1(319)-934-3552
>
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