"pounding"

[Jason Kanter]

Jason wrote:
>> One direct, sharp blow is sufficient. While gently manipulating the tuning
>> pin, you are pulling the short distance between pressure bar and tuning pin
>> into much higher tension than the tension on the speaking distance of the
>> string. The purpose of the hard blow is to equalize these two tensions. If
>> they are not equalized at the time of tuning, they will equalize more slowly
>> (and the piano will go out of tune rapidly).
Susan replied: 
> Theoretically, I don't see how this would work out. Maybe some wiser heads
> will inform me of what's really happening. Picture: the part of the string
> up near the tuning pin is too tight. So you give a good sharp blow to
> "equalize" it. The good sharp blow raises tension in the speaking length,
> and presumably pulls even harder at the length near the tuning pin.
Jason re-thought:
Actually, when you pull the pitch up you go a little past and then settle it
back to set the pin. The result here is that the tension above the pressure
bar *may* now be less than that of the speaking distance. The sharp blow
equalizes it IF it is unequal. (Hopefully the pressure bar is not rusted and
its friction is trivial compared to the string tension.) And as some players
will be using sharp blows, the tuner needs to know whether a sharp blow will
put the string out of tune. However, there is no need to use repeated sharp
blows while listening.