Pitch Window Method for Stability

Here’s my Pitch Window Method for stability.

Suppose you come to a string and you have to lower the pitch a tiny bit. The first thing I do is assume that the NSL tension is near the bottom of the tension band that produces stability. Now, what I do is a gentle flex of the pin in the direction of the string. This flex has to be very small because we don’t want to damage the pin block.

Now, if the pitch does not go down, that means the NSL tension was not near the bottom of the tension band.

So, that means that the target pitch is not available to us for the pin foot orientation that the pin currently has. 

So, I need to turn the pin foot by the smallest amount possible, and I have to do this without having a change in the pitch.

If I can get the pin foot to move, without having a change in the pitch, that means that the NSL tension now must be lower in the tension band.

Now, I will try the gentle flex in the direction of the string and hope that the pitch will drop by the smallest amount that I’m looking for.

If the pitch does not change, then I must do a very small nudge of the pin foot again and repeat the flex.

Using this method of flex, move the pin foot, flex, move the pin foot, I am able to make a very small change in the pitch and also know where the NSL tension is and therefore leave it slightly high of middle so that I can have good stability.

I hope that helps. If you have any questions, don’t hesitate to ask for clarification.

Note: it is the unbending or unflexing of the pin that puts the tension back into the nonspeaking length. If the nonspeaking length is very long, then the unflexing will not put very much tension back into the nonspeaking length, and the string may be unstable. If the nonspeaking length is very short, then the unflexing actually might put so much tension back into the non-speaking length that the pitch actually rises!

This is called Hooke’s Law.

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6 Responses to “Pitch Window Method for Stability”

  1. Don says:


    NSL is not a useful abbreviation. If you write it out in full the first time it is used in each separate email, it would become clear what you are talking about.

  2. Cobrun Sells says:

    I’d assume that the opposing arguments of massaging the pin would be that over bending the pin will permanently kink it (making adjusting the pin uneven in the future). But, what do you do when the NSL is really long? I don’t imagine you twisting or bending the pin too much. But, then the string is still unstable because the NSL tension is too low for stability. So, do you resort to pounding the key on the piano to stabilize the string if the NSL is too long for any sort of massaging or twisting of the pin?

    • Good points.

      For long NSL I use slow pull going sharp. The sharp motion puts the NSL tension at the top of the tension band and the untwisting lowers it a bit to leave it slightly high of middle.

      I usually use a 3:00 position but if the NSL is a bit shorter, increasing unbending effect in NSL tension, 12:00 reduces the unbending and reduces the increase in NSL tension due to unbending.

      A test blow or bend test can confirm.

  3. renato says:

    Dear Mark,
    today i have followed your tip and it worked very well!
    let’s see if i got it.
    A string is stable.i must lower a very,very little amount.I push back a very little and no change of pitch,it means the nsl got its tension at the right point,the pin is firmly set,that’s all i’m allowed to do.Perfect balance.Now the only way is to turn the pin in its socket just enough to decrease the nsl tension(not the pitch), so that now pushing back a little will influence the speaking lenght too and i will also lower the pitch.Now if it’s done properly the untwisting or unbending of the pin will increase the nsl tension without changing(raising) the pitch but setting the balance needed to gain stability.Is it correct?(we’re discussing of course the smallest tiny movement we need to gain for istance for perfect unison)

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