Scaling problem

[Ron Nossaman]

>
>     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