psycho-acousti-what?

[Daniel Gurnee]

on 2/13/01 12:51 PM, Mark Cramer at cramer@BrandonU.CA wrote:

When a pitch is more powerful than the rest of the  piano and the sustain is
short, look to lack of impedance at the soundboard, in that area especially.
The lack of impedance is called compliance.  The very free motion of the
soundboard saps the energy of the string causing a lowder tone with less
sustain. The correction can be increasing the stiffness of the soubdboard
bridge system or increasing the weight in the problem area.  That can be
done simply by screwing a weight to the back of the soundboard behind the
bridge. The same problem occures at the bass/tenor break with the same
solution.

Daniel Gurnee RPT, retired from HSU, CA

  

> A year ago, a client told me she had several notes on her (Baldwin) console
> that physically hurt her ear when she played them.
> 
> I tried the notes, which were the first few above the tenor/treble break,
> and noted they were a bit harsh, but thought (to myself) maybe she was
> exagerating a bit.
> 
> I tried them as major thirds, which she had been playing, and nothing. Then
> I turned my head a bit in her direction, played them again, and "Ouch!" It
> was as though someone was pressing their finger between my upper jaw-bone
> and ear!
> Definitely painful!
> 
> I remember trying every bit of "voicing voodoo" I know, to no avail. Indeed,
> I had forgotten about this til yesterday. A music teacher with a Baldwin (no
> I'm not picking on brands) 52" vertical, who never seemed pleased with the
> treble, said the magic words; "it hurts!"
> 
> It's exactly the same phenomenon! At first listen, these hammers "sound"
> soft at the crown, but hard, very hard in the shoulders. The sound is a big
> muffled boom, but with little sustain.
> 
> I went at C5 on the big upright with a single needle to probe the shoulder,
> certain I would fined hardener,.. but nothing. The shoulder felt is soft,
> much easeir to needle than a Renner, Yamaha, etc., even at the crown. I
> needled all over the place, and could not change the sensation of the tone
> one little bit!
> 
> What is the problem?
> 
> If you have experienced this, you will know exactly what I'm talking about,
> and I would sure love to hear from you. Yes, especially if you've been able
> to solve it.
> 
> On my next visit, I'm taking a variety of hammers to test, but I'm not so
> sure hammers are the problem!?
> 
> thanks, as always
> 
> Mark Cramer,
> Brandon University
> 
>