Greetings Jim,
This must qualify as one of the most open questions on
the list for quite some time. And there is no simple answer due to a
variety of variables.
The number one factor in longevity of tuning stability, given a
competent tuner, is bridge, string, seating and integrety. If the
string is not seated on to the bridge and in good contact with the
bridge pin, the pitch will wander and you will have a false beat.
Regardless of tuning technique, good quality stability is not possible
under this condition.
Age and condition of strings, along with the friction factors also
enter into the debate. A new piano will benefit greatly with regards to
stability, with very firm setting blows, the wire is more elastic, and
has not started to show the signs of necking at the pressure points. The
same piano 10yrs hence will be quite stable with much less force applied
to the blows, providing it has been well maintained.
The amount of pitch raise also is a factor, a quarter of a semi tone
raise, needs
two corrections, to attain a stable tuning, raise about 25% sharp of the
amount that the piano is flat and pound hard, now the scale should be in
reasonable tuning range. On a high quality grand I would also reseat the
strings again, before fine tuning.
As an observation on new Baldwins I have found that a double hard blow
is needed, due I think to friction factors, the comparable Yamaha
however is just as stable will a less agressive approach.
String, hammer, mating is important, in a badly aligned hammer, string
A may be struck with twice the force as string B, hence the firmly
struck string will go out of tune quicker than its counterpart. On
vertical pianos it is critical at the bass/tenor break.
The following also has an effect on the customers perception of tuning
stability.
1. False beats, I've never had a customer tell me that a particular
string is false, the compromise tuning out, of beats will last for a few
days, and then show quite audible signs of drift.
2. Phasing, due to badly shaped or travelled hammers.
3. Vee bar noise, caused by badly voiced or over hard hammers, and badly
grooved pressure bars.
If you have the any of the above faults all the pounding in the world
will not help.
Very bright hammers seem to show tuning discrepencies much more quickly.
It may seem that I have wandered off topic, but the question can not be
answered in a black and white manner, the variables are too numerous,
and that is one of the things that makes this such a wonderful
proffession.
CAN OF WORMS?????????? I GUESS SO.
Regards Roger
> I would appreciate knowing what some of you other tuners think about
> pounding a piano hard vs soft pounding. One tuner I know pounds pianos
> really hard and his tunings tend to be very stable and long lasting.
> But I have also heard other tuners say that pounding hard during the
> tuning process is not good. Any thoughts on this?
>
> Thanks,
> Jim Turner
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