[pianotech] What's causing this vibration?

[Tom Driscoll]

List 2nd try at this post . For some reason the first attempt got lost
T.D.

John,
    A few things come to mind . First is to do what you have done already.
Look , listen, tighten , touch . On thing that can help is whilst the
pianist is activating the buzz get your head right over the board .
First put one ear down toward the board wherever it seems the loudest then
quickly turn the other ear down. Essentially crawl all over and under the
piano doing this.  I'm not sure why but for me the stereo effect of doing
this can lead me toward a location. Finding where it's coming from is a good
start toward a solution.
    If I think it's a case part  I remove the lid and listen then remove
each other part with a test each time.Top stick, stretcher, even the music
desk holders inside the rim. Sometimes the problem follows the case part.
Also remove the lock from the stretcher if the stretcher can't be removed.
    I'll bet we all have goofy stories about this type of problem so here is
mine. A long time client with a fairly new Bosendorfer calls about a buzzy
awful noise . We both do just as you did with your client.
No luck and I was getting frustrated so I stepped back while she played.
Problem solved  !  It was an old rusty metal bathroom medicine cabinet on
the floor 12'  from the piano waiting to go out to the curb on trash day. We
had both heard the noise IN the piano.
      Good luck,
 Tom Driscoll


----- Original Message ----- 
From: "Rebecca and John Silva" <misc at rjsilva.com>
To: <pianotech at ptg.org>
Sent: Friday, March 09, 2012 6:59 PM
Subject: [pianotech] What's causing this vibration?


Hi,

When playing a particular note on a piano I saw today (Baldwin L) a harsh 
vibration would sound. The vibration would only happen for a moment (1/4 
second?) even while the note continued to sound, it was about 1/2 the volume 
of the note and only happened when playing hard. I worked with the owner for 
about an hour trying to figure it out and we were only able to determine it 
is based on pitch—if I detuned the note it would go away, and if I detuned 
the adjacent note to the offending pitch that new note would cause the 
vibration.

I looked at everything I could, ensured every part/screw I could see was not 
loose, tapped on the bridge pins, and tried to figure out where the 
vibration was coming from.

Does anyone have any suggestions of where to look? Any common but elusive 
offenders? Two highly regarded technicians in the area were also apparently 
unable to figure it out.

Thanks!

John=