Problems With Duplex Scaling Of Pearl River Grands?

[Richard Brekne]

Hi Mark.

I'd be surprised if you did notice any real difference. At least given 
the fact that the actual pitch of duplex sections is one of the most 
neglected areas of what piano techs do on a daily daily.  One hears many 
claims back and forth about whether this or that relationship to the 
speaking length, about duplex pitch stability, about the basic 
precepts.... and gawd knows what about the back length in general. But 
I'd bet its the fewest of the few who've actually spent any real time 
working with any of these lengths to see what can and cant be accomplished.

Ed McMorrow has done some study on the front duplex, and  I find his 
conclusions and advice to work out well in practice.  As far as the back 
duplex is concerned... I don't know so much myself....yet... but I have 
found out that tuning back length unisons turns out to be a far more 
stable affair then I've been taught to believe by most on and off this 
list. 

Muting off more then the lower treble and bass lengths is something I've 
never found necessary.  Nearly always a customer complaint has to do 
with a very few tones in the higher treble that seem to have a kind of 
false-false beat caused by the fundamental of the note in question being 
interfered with a back length somewhere lower down.  Adjusting the pitch 
of that back length alleviates the problem. If one just plain doesn't 
like the extra overtones... well what can one say... :)  Cant say I've 
ever run into that situation myself.

Cheers
RicB


    I've never noticed that the sounds produced from the duplex'd
    sections of Pearl River grands were any more annoying, pleasing, or
    interesting than that of any other maker who relies on esthetics to
    determines the placement of the duplex mounds.

    I doubt if the muting you mention was done because of "not pounding
    his tunings in".  It seems far more likely that the listener didn't
    like the harmonic contribution of the duplex and had the tech mute
    off the area.  If that's the reason, no matter how the piano was
    tuned, I'll bet the listener would have had the same objections.  

    I've felted duplex'd strings myself, it's not all that uncommon of a
    complaint.

    Hope this helps.

    Mark Wisner