[CAUT] damper chirp

[Mitch Staples]

The way I understand it the chirp happens when the two vibrating strings
contact the damper felt causing it to vibrate, since the third string is
stationary the felt strums it a little, causing the noise.

If it is happening in the alto area where there is a block felt and a double
wedge felt on the damper head usually you can reduce it a lot or eliminate
it by replacing the wedge with a block.  Also limiting the movement of the
unacorda so all three strings continue to sound but are hit between the
string grooves is a good idea.

I think it's also a good idea to tell the performer what is happening so
they understand and maybe don't it anymore.

Mitch Staples
Ohio State University

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org]On Behalf Of
geinert at drtel.net
Sent: Thursday, March 13, 2008 9:15 AM
To: caut at ptg.org
Subject: [CAUT] damper chirp


Last night I was at a Bosendorfer Imperial I service.  A couple months ago I
regulated and voiced it.  Last night, when played with the shift pedal,
whenever
the dampers were lowered they would chirp.   It was not completely unlike
what
a glazed damper sounds like, but these are pretty new, and definitely not
glazed.

When I had regulated this, too  bright/not enough warmth were the
complaints.
When voicing una corda, even though I know Bosendorfer does not set the
shift
to clear the left string I did it anyway.  I tried to figure out why not to
at the time
and couldn't come up with a reason.  Last night when the dampers were
chirping, I checked right away to see if the clearing string was the
problem, and
it was.  Setting the action shift back to put the strings between the
grooves and
the chirp went away.

I am interested to hear theories of why that would  be.  No other piano I
have set
with the left string to clear when the action is shifted does this.(that I
know of
anyway)

Tim Geinert