[pianotech] What's causing this vibration?

[Richard W. Bushey]

Had a similar issue to Doug's on a grand about a year ago...spent an hour or 
two trying to locate a little metallic buzz that seemed to come from beneath 
the piano in the pedal region. It had a piano disc system which made it that 
much more fun to isolate.  I lubed what I could then decided to start 
tightening any screw I could find...which meant ANY screw I could find 
(besides certain plate bolts, nose bolts, or regulating screws that of 
course are not to be tightened). Come to find out, similar to Doug's case, 
it was also loose washers that were vibrating on the screws that held the 
sostenuto mechanism to the back wall of the action cavity, if I remember 
correctly. Before I tightened them down, I tapped my finger on the sostenuto 
frame and sure enough, the washers started dancing.  I tightened them all 
down and whala!  I guess the good news is that everything else in the piano 
got either a lube job or tightened up that day too...which it  probably 
needed done anyway!  Very frustrating....especially when you feel you're in 
a rush being on the clock and such.

Some other's have made the point from time to not always assume the 
vibration is coming from inside the piano. Loose wallpaper, dried up labels 
in a piano, loose glass in a picture frame, etc, etc, etc. can sometimes 
buzz at certain frequencies, we all know that a snare drum will go to town 
vibrating when the piano is played if the snare is left on.  Sooo it can get 
quite interesting at times trying to locate those pesky noises.  Sure is 
satisfying when you find them though!

Hope you track it down!

Richard W. Bushey
Richard's Piano Service
www.RichardsPianoService.com
Rbushey at RichardsPianoService.com
573-765-9903




----- Original Message ----- 
From: "Douglas Gregg" <classicpianodoc at gmail.com>
To: "pianotech" <pianotech at ptg.org>
Sent: Saturday, March 10, 2012 10:46 PM
Subject: [pianotech] What's causing this vibration?


> John,
> I had a small Setengren  baby grand with a very similar problem.I had
> sold this piano and  guaranteed it, so I had to find it. But this one
> was intermittent and seemed to be worse when there was high humidity.
> The owner mostly played after midnight when it was really quiet and he
> was very sensitive to this noise. I was convinced it must be related
> to the soundboard. It never seemed to be very bad when I was there so
> I took the piano back to the shop and put a humidifier near it. It was
> subtle and I could not find it. I even turned it upside down and tried
> to wick glue under any possible loose ribs or the rim. I was all over
> this thing. I thought it had to be gone. I returned the piano to the
> house and it was OK for a week and then came back. This time, I was
> there when it was making noise and it was loud enough to track down.
> It turned out to be three screws in the back action that had loose
> washers hanging on them. I still don't know what the screws were for
> but the washers had done it. I removed the washers and it is fine now.
> The humidity must have just been a red herring.
> I spent about 12 hours on that one.
>
> Doug Gregg
>
> Message: 1
> Date: Fri, 9 Mar 2012 18:59:30 -0500
> From: Rebecca and John Silva <misc at rjsilva.com>
> To: "pianotech at ptg.org" <pianotech at ptg.org>
> Subject: [pianotech] What's causing this vibration?
> Message-ID: <6DA1BC72-C295-45AB-BC4D-AB9680FF88A2 at rjsilva.com>
> Content-Type: text/plain;       charset=utf-8
>
> 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 


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