Yamaha GH-1 Grand

[Billbrpt]

In a message dated 98-02-28 23:31:57 EST, you write:

<< Does this model have a problem in the stringing scale?  Shoud I re-scale
it, or does Yamaha have a new scale for it?  I do not want to my client to
waste $$$ on rescaling and restringing it if it will not help.   
 I am not sure it is voicing or if my ears are going whaky.  Your advice will
be much appreciated. >>

   Yes, there is a problem with the low tenor.  You can tune it but it will
always be unstable and the "shallow" sound you are hearing is normal for this
piano.  The numerical values that result in good octaves,  3rds, 4ths, & 5ths
will not be those provided by an FAC or similar program.  
 
     The inharmonicity of these notes is way off from where it normally would
be. The tension on the lowest six unisons is very low.  Imagine any other
piano with a normal and good sound somewhere in the midrange and taking six
notes in a row and lowering their pitch by two whole steps or more.  You'd
have that same sound you are encountering with the Yamaha GH-1 in the low
tenor.  You could still tune those notes either by ear or with the SAT but
they wouldn't sound right to you, voicing would not help much and their pitch
would be very unstable with the slightest change of humidity.

    The solution is a partial rescaling of this section.  Yamaha provides a
kit for this.  All you have to do is change six agraffes, six dampers, drive a
few new holes for some hitch pins and replace the plain wire unisons with
wound string bichords.  The middle tuning pins with no string attatched are
simply left at the same level as the others for appearence sake.  You can do
it in a few hours.

    This is not the only piano which has this problem.  You may find a similar
problem with any small grand or verticle with notes anywhere below D#3 in the
tenor that have plain wire.   If you do not have the ability or want to for
any other reason not to go to the trouble of designing wound strings for this
section, you can use heavier wire than the original up to a point, then you
can convert to very heavy plain wire bichords.  You will find some pianos
already scaled that way.  While the wound string conversion is the best
solution, any solution will always be somewhat of a compromise. 

   The heavy plain wire trichords and bichords will have a very powerful,
"boingy" sound to them but you can voice the hammers to compensate.  Too much
power and higher inharmonicity will always be the result of using heavier wire
in this section.  If you ask me however, I would rather deal with a loud
brassy tone than a weak, "shallow" tone, as you describe it, which is the
result of wire which is at such a low tension than it is loose and flabby.

    James H. Donelson RPT's PIANO REBUILDERS' HANDBOOK OF TREBLE STRING
TENSIONS, which may still be available from the supply houses, can help you
analyse the problem and find the right wire.  If you look up the tension
values for this section of the Yamaha GH1, you'll find the figures to be
extremely low. 

    If you decide to use very heavy wire bichords, the wire size you choose
may even be so heavy that it is off the list.  You have to remember that if
you make this decision, you are dropping one of the strings and therefore some
of the load.  It would not be out of line therefore to use some of the
heaviest wire available, 22-25 in the lowest bichords.  Donelson's book did
not really cover the idea of plain wire bichords.  Plain wire trichords with
very heavy wire would usually not be considered and therefore his list stops
short of providing the data for the heaviest wire for these string legnths.

    Bill Bremmer RPT
    Madison, Wisconsin