Vibrator as Diagnostic

Ken Jankura kenrpt@mail.cvn.net
Wed, 14 Jul 1999 19:39:08 -0400


>Bill Ballard wrote:
>> 
>> I'd been listening to a grunting sound, like a fallboard-to-front-stretcher
>> or loose metal lyre brace, during the tuning of a Falcone 74, sympathetic
>> to F4. In trying to chase it down, the best I could come up with was that
>> it was coming from inside the action cavity (loud and clear). So I fastened
>> anything inside I thought could be making noise: damper upstop rail, damper
>> assy mounts, action brackets to key frame, the rails on the key frame. At
>> first it seemed to go away when I pried downward on the action brackets
>> from the pinblock. The key frame bedding was quite solid. I could not
>> follow the sound over the strings, or under the keybed.

My recent sound like this was in a S&S ex-player M, and it was much more
like a hee-haw overtone, 4th above then octave below. Worked velocity
dependent on F5,F#5,G5. Turned out to be the key upstop rail screws. Had me
going though.
Ken Jankura
 
 


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