Yamaha Duplex Scale

[Wallace Wilson]

Mark,
        At one of the conventions during the past couple years, I
observed a
demonstration of the Franklin Duplex Slider.  There are all kinds of
ways, of course, to move duplexes.  He includes w his tool a book that
gives duplex lengths for all the pianos he could find.  
        I'm not plugging this thingee.  I am asking if others have used
it to
good advantage, or whether his book of duplex lengths is too mechanistic
to be valuable.  As Mark observes, many mfgs set up their duplexes to
pitches other than what one would expect.  I expect their reasons may be
anything from gaining maximum tone and ring to poor planning.  Comments?

--Wally Wilson, RPT
  Ravenswood, WV


Mark Bolsius wrote:
> 
> >  As for the Yamaha specifically, measure them and compare
> > against the speaking lengths. Then do the math. Or pluck and ponder.
> >
> >
> > Ron N
> 
> I can see the point of the original question, and it's not a stupid one!
> 
> The back duplex pitches seem to be consistently a semitone out from what you
> expect. I don't have a Yamaha grand within easy reach to check this on, so I
> couldn't tell you if it's a semitone up or down but it's very
> consistent...not a mistake.
> 
> Whereas Fazioli will tune those cute little gizmo's perfectly to whatever
> they have decided on each part of the piano.
> 
> Curious...
> 
> Cheers
> Mark Bolsius
> Bolsius Piano Services
> Canberra Australia