Problems With Duplex Scaling Of Pearl River Grands?

[Andrew and Rebeca Anderson]

Rex,
Firm test blows will usually render enough tension through the bridge 
pins to the rear duplex to bring it up to tension and into the 
designed tune.  Mind you the rear duplex is not usually perfectly 
tuned and that on purpose to avoid zingers.  On new pianos that 
usually is sufficient.  Some pianos coming from China have been 
exposed to rather caustic air and may have some corrosion at the 
contact points to overcome.  I don't know if Pearl River is one of 
these where adequate precautions have been taken to prevent this.  I 
am aware that Geneva International (Nordiska and Weinbach) goes to 
great lengths to prevent corrosion of piano strings because of 
quality control problems that cropped up.

Essentially the technique involves pulling the speaking length 
significantly over pitch and then tightening hitch-pin loops, 
straightening the wire path from the hitch-pin to the bridge pin, 
massaging the speaking length wire to pass tension back through the 
pins towards the hitch pins, gentle seating on the duplex bar and 
then gentle (!) tightening of the curve from the rear bridge pin to 
the hitch pin.  Follow that by gently tightening the front curve off 
of the bridge pin, tuning the speaking length down to pitch and 
levelIing the strings.  Where there is a front duplex gently 
tightening the curve on the non-speaking side of the capo and on the 
duplex bars will improve the sound there too.  I've noted that most 
affordable new pianos need some of this basic string-voicing done 
including string levelling up front and hammer shaping before they 
start to sound decent (especially lower tension scales).

Depending on how well a neglected piano responds to a pitch 
correction, I usually do some string voicing with a large pitch 
correction to get the piano sounding good again.  Again this can be a 
function of corrosion on the contact points that is difficult to 
overcome by firm test blows.

Part of keeping pianos cheap is passing off the fine work to the 
dealer technician.  If Steinway does it, why shouldn't all the other 
less accomplished piano makers do it too?  Of-course that means a lot 
of things can slip past quality control but ultimately the dealer and 
the dealer technician are the final quality control agents and they 
vote with their dollars; behind them is the customer facing the 
Yankee dictum, "Buyer Beware."

YMMV,
Andrew Anderson, a Technician Dealer


At 03:36 PM 8/18/2007, you wrote:
>Andrew
>
>You made the following statement in a reply to this thread. "If the 
>rear duplex is not up to pitch, there is a tuning method to work on 
>that specifically."
>
>Could you explain the tuning method.
>
>Thanks
>
>Rex
>Roseman Piano Tuning

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