Scaling problem

[David M. Porritt]

I have tuned one GH1 that was made during a brief time where they had
wrapped bichords from #26 - #33.  MUCH improved!  Why they ever went back
to the plain strings there is beyond me.

I measured the inharmonicity on a regular GH1 and #27 had 28.5-cents at the
8th partial - just in case you were wondering why the triple octave (B2 -
B5) sounds so bad.

dave

*********** REPLY SEPARATOR  ***********

On 5/19/01 at 8:16 PM Ron Nossaman wrote:

>>
>>     I've had some partial success with carefully doping the hammers, and
>> voicing the bass down, plus leveling strings, straightening termination
>> points etc., but not to any totally satisfactory result. 
>>     Got any good advise? I'm all ears.  
>>  
>>     Or is it just poor design?
>>  
>>  
>> Kevin E. Ramsey
>> <mailto:ramsey@extremezone.com>ramsey@extremezone.com 
>
>
>
>Kevin,
>I'm a long way from being a scaling sage, but I'll vote poor design with
Joe.
>The only claims I've heard for improving the problem with voicing are from
>Roger Jolly, but he's just blowing steam. Sorry Roger, couldn't help
myself.
><G> A couple of years ago, tuning a GH1B for a dealer, I was tired enough
of
>the lousy low tenor that I took a little extra time and got some
measurements
>from the piano to check them out on my scaling spreadsheet. I measured
core,
>wrap, and speaking length of notes 24-31, with the break being at 26/27. I
>found the original break% of #26 at 54%, and #27 at 21%. Tension,
>inharmonicity, and impedance were just about that smooth across the break
too.
>I played around with the scaling numbers at the transition and ended up
with a
>reasonable (not good, but reasonable) break with the original speaking
lengths.
>I substituted four bichord unisons in the low tenor and it looks like it
would
>help. A break% of 54 at #26, and 45% at #27, with a smoother tension,
>impedance, and inharmonicity curve would about have to help some. While I
agree
>with Ron O that this is a far less than ideal configuration, I was curious
to
>see how close I could come aurally. Unfortunately, I don't have a GH1B to
try
>it out on, so I can't say for sure what the results would be. My
impression was
>that this can't be really fixed with the original bridges, only made less
bad -
>and that with more modifications than just changing some strings. Starting
at
>the drawing board, I'd want to put the break at #31 or #32 in the first
place
>in a piano this size, but for some reason Yamaha chose a lower point in
the
>scale. I didn't see anything particularly obvious to make me suspect
soundboard
>problems. It does seem to be the scale that's the primary problem.
>
>Now what I want to know, given the obvious wretched sound of these things
>across the break, where did this scale design come from in the first
place? I
>don't see how it could have been "designed" this way and been allowed out
the
>door after hearing the results. Who does Yamaha's scaling, and why can't
they
>fix this themselves?
>
>I don't buy the story that the GH has to sound bad to sell the C at the
higher
>price. If it was supposed to sound lousy, they wouldn't be contracting
these
>scaling fixes from independent techs.
>
>
>Ron N




David M. Porritt
dporritt@swbell.net
Meadows School of the Arts
Southern Methodist University
Dallas, TX 75275