longitudinal mode?

[Andrew and Rebeca Anderson]

I tuned this piano again a few days later for a master class.  The 
lid had been restored and the percussion equipment was all gone by 
that time.  I could not find that elusive buzz anymore.  Either 
something in the hinges (hinge-pins?) was sympathetically vibrating, 
or more likely the snares right up close to the rim were doing 
it.  Funny thing is, I could of sworn it was coming from inside the piano.

Chalk another one up to "experience"
Andrew Anderson

At 07:36 PM 9/30/2007, you wrote:
>All strings of the unison excited the same short buzz about an 
>octave +.  Had me chasing around a while for something but I 
>couldn't isolate a sympathetic resonance.  I didn't think of lifting 
>because all three were making the sound.  I could try it.  I did 
>lift and level these strings last year.  The piano is on full 
>climate-control with a cover most of the time and there has been 
>very little variation in pitch.  I noticed it today with the lid 
>off.  It was right next to the snares but the sound sure seemed to 
>come from within the piano.  I'll have to check again when the 
>orchestra instruments are distributed back to their classrooms/owners.
>
>Andrew Anderson
>
>At 03:36 PM 9/30/2007, you wrote:
>
>>>Tuned a D this afternoon to prep for this afternoon's 
>>>concert.  A#6 had a short buzz a harmonic above the note.  I could 
>>>not find an offending duplex (front/back) to mute.  Would this be 
>>>a longitudinal mode?  Got any ideas to chase this one down?
>>>Andrew Anderson
>>
>>Hi Andrew,
>>I'd think not. The longitudinal would be way up there in pitch, and 
>>I'm not sure they're even audible that high in the scale. Did you 
>>isolate unison strings to see if only one made the noise? I'd try 
>>repositioning the strings a tad, and lifting and leveling that unison.
>>Ron N
>