Singing Strut

[Doug Richards]

     Charles et all,
     
     Another solution might be to ADD mass to the strut in question.  If 
     another mass was attached with industrial strength double-sided tape, 
     it would act as a tuned absorber.  You would have to experiment with 
     the amount of mass, but it will work.  Although I haven't tried it on 
     a piano it does work on other real life stuff (like disk drives).
     
     doug richards
     Associate Member #12580
     San Jose, CA.
     
     
______________________________ Reply Separator _________________________________
Subject: Re: Singing Strut
Author:  "Jim Coleman; Sr." <pianotoo@IMAP2.ASU.EDU> at SMTP 
Date:    11/24/97 12:23 AM
     
     
Hi Charles:
     
If leaning on the strut caused the vibration at that pitch to stop, then 
I might suggest that a retro-fit bar would be in order. You know the 
removeable bar on a Steinway concert grand. I envision a bar which would 
be clamped between the offending strut and another strut. This would 
damp out the original frequency since it would change the free 
vibrating length.
     
If this is a resonant frequency, it probable happens on other pianos of 
the same size and make. the factory might be interested in what you 
come up with as a fix.
     
Another idea just off of the top of my head would be to temporarily 
clamp a piece of maple 2X2 to the side of this offending strut to see 
if that would make a difference. If this is the Bass strut, the 
auxiliary piece could be bronzed. If this does not stop the singing 
strut, then, there may be some other cause which your leaning on the 
strut stopped.
     
>From the customer's standpoint, changing pianos would probably be the 
best thing to do, but from the practical standpoint, you wouldn't just 
throw away an almost perfectly good piano when something could be 
done to eliminate the problem. The factory needs to know about this so 
that if they have other complaints of this same nature, they can take 
steps to correct it.
     
If the customer has merely latched onto this phenomenon to renege on a 
deal, then you certainly don't want to be caught in the middle of a 
legal problem.
     
Jim Coleman, Sr.
     
PS What model is this? I may be able to investigate this at our local 
dealer's showroom. Write me privately if you would like me to look for 
a similar problem here. JWC.
     
On Sun, 23 Nov 1997, Charles E Faulk wrote:
     
> Del 
> 
> Fortunately for the customer, this piano is brand new; and the purpose of 
> my visit was to investigate a warranty related complaint. 
> 
> Although I couldn't tell the customer, it looks like a replacement of the 
> piano might be in order. I hope that other similar models (Petrof) don't 
> have the same problem. 
> 
> I wonder how one might actually repair such a problem. I had to literally 
> lean on the strut to stop it from vibrating. 
> 
> Thanks again.
> 
> Charles Faulk
>