Pitch Raising Your Piano

Piano Pitch Raising

By James Grebe

Pitch raising a piano is probably one of the most troublesome experiences a piano can go though.  I will explore with you what happens when gross pitch change has come to your piano.

          First of all, to keep your piano at standard pitch requires regular, frequent tuning.  The piano will hold the tuning much better when pitch is not altered greatly.          Imagine, that as the string comes off the tuning pin, it gets divided into segments along it’s entire length.  The first segment is between the tuning pin and the capo bar leveling the string to its neighbors and giving it up bearing.  Another segment is formed between the capo bar and the front bridge pin (the speaking length).  Then another between the front and back bridge pin (at this point the string is deflected right at the front  pin and left at the other) and lastly from the back bridge pin to the hitch pin.  If the piano has a duplex scale it is deflected again up before the hitch pin.In order to cause the speaking length of the string to change pitch the first segment moves when the tuning pin is turned which then causes the 2nd segment to move which causes the 3rd segment to move and on to the hitch pin.  After all the segments have changed it is the problem of getting all the segments to have an equal amount of tension in order to get stable tuning. Changing the tension on the speaking length is like a freight train beginning to move on the track.  The moving of the speaking length is not a direct result of pin motion but an indirect result.

Once all segments are moved, a short time allows the segments to equalize their respective tension levels.  Playing the piano will do this in fairly short order, which is why I encourage a lot of playing before the first and second tunings of a pitch raise.  This time period allows the case (back support) and plate and soundboard to readjust to the increased tension and will have worked their way out by the time I come back for the second tuning.  It took a long time of neglect for the piano to get this low and it does not come back to stability without a fight.

     The soundboard, under the increased tension, will sort of compress under the increased tension and then expand to equalize it’s crown and move the tuning around with it.

If you notice, I try to bring up the pitch in groups of 2 or 3 octaves at a time to spread the increasing tension over as much of the piano as possible so as not to put so much pressure on just a small area..  Without doing that would cause a great deal of unneeded stress on your piano.  As you may notice, as I go up the scale the treble gradually becomes flatter than the middle due to the fact that a given tension level has a greater effect as the string become shorter.

The bass section is almost like a separate piano in the same case and generally will not move around as much as the plain steel wires, because the bass strings are individually tied and being longer, tension does not have the same effect on them as it does the treble.

Pianos 10c to 20c low should be tuned again in 2 months and every 6 months after that.  Pianos that are 20 to 25c low should be tuned in 1 month and then every 6 months.  Pianos that are 25c or more should be tuned in 2 weeks and then in 3 months followed by every 6 months.  Pianos receiving hard use or go through many changes in temperature or humidity will require more frequent tuning.

String breakage is always a potential problem in pitch raising and I raise pitch very carefully to avoid this as much as possible.  Still, especially when rust or corrosion is present, they will break occasionally.

          You will find that once A-440 is achieved the best tone the piano has to offer will be presents it was designed to have that amount of tension on the strings and soundboard

Copyright,2008/Yesterday Once More Publications, James Grebe

© Copyright 2017 James Grebe. All rights reserved.