Pitch Raises (was: Birdcages)

[Z! Reinhardt]

Comments below ...

----------
From: Jay/Deb Mercier <mercier@minnewaska.com>
To: pianotech@ptg.org
Subject: Re: Birdcage, more....regarding pitch raises
Date: Wednesday, October 14, 1998 11:59 AM


>>snip!<<

>>Now I find it tricky to know how much I raise the pitch over A=440 in
order
for the pins to settle back to A=440 by the time the pitch raise is
complete.  Many times it will fall into the correct pitch perfectly, but
sometimes I run across an old, stubborn upright where the pins stay where I
bring them up, meaning that I have to lower the pitch after the raise.  And
then there are the pianos that no matter how high (within safe reasoning) I
overextend the pitch, it still needs that second pitch raise - I'm finding
this common on Samicks (but I'm not picking on Samicks).<<

++  A number of piano *breeds* take additional passes through the 5th-7th
octaves.  I too have noticed that Samicks are very prone to pitch drift in
that range, but once you figure out what it will take to *outsmart* that
tendency, then they are pretty straight-forward to tune.  Then you'll find
that what works on Samicks may not be the best idea for pianos made by
another manufacturer.++

>>Is this procedure common/safe with anyone?  What do you do when guessing
how
much to overextend the pitch for it to fall back to A=440?

Any feedback is appreciated and thanks in advance!

Jay<<


++As you've already found out, how much overpull depends on the piano. 
Furthermore, each section of the piano responds differently to pitch raises
with some sections requiring heftier overpulls than others.  It is for this
reason that I like to listen to all of the octaves before I do anything,
just to determine what level of overpull would be appropriate where.  Very
often the treble takes additional passes or more severe passes (within
reason) than the rest of the piano, particularly the 5th and 6th octaves. 
The bass usually takes much milder overpulls than the rest of the piano. 
To compound matters, the amount of overpull necessary is also dependent on
your technique.  The faster you can work, the less overpull you will need,
probably because the notes you had tuned will have had less time to drift
before they are used as reference notes for tuning other notes.

The SAT calculates a 25% overpull in its pitch raise function.  My tuning
technique is such that I get the best results by fooling the SAT into a 10%
or less overpull in the bass, 15% overpull in the midrange/temperament,
25-30% in the 5th-6th octaves, then 15% in the top.  These overpulls are
based on what is found in each section as I get to them, so the actual
deviation from the *ideal* pitch for each section will be different.  I
blast through the pitch raise passes as fast as I dare, unisons as I go,
and have found that the faster I can go, the more "workable" the results
are afterwards.

This applies to pianos that are less than 100 cents flat at worst.  For
pianos that are more than 100 cents flat ... clear the area or hang on to
your seats and hold your ears while I do a pass or two to bring up the
pitch to something workable without overstretching the strings. 
(Thankfully I'm not called upon too often to attempt tuning these pianos.)

In days before the SAT ... well, yes, there were some interesting cases,
particularly in the early days of my career.  I happen to have a really
good sense of pitch so I could get away with some really rude ways of doing
pitch raises with the simple goal of doing them as fast as possible.  All
that mattered was that the strings weren't pulled beyond their natural
elasticity.  (You'll develop a *feel* for where that is.)  On several
occassions I horrified the customers with the intervals I was using to tune
the 5th-6th octaves, but when all was said and done (and very rarely with a
broken string), they had a piano they could play and enjoy again.

Perhaps someone could elaborate on what aural techniques work best when
their sense of pitch is considerably less than *perfect*?++

Z! Reinhardt RPT and PitchBitch
Ann Arbor  MI
diskladame@provide.net




>HI Phil:
>
>I've always looked at pitch raising as kinda' like cutting off a dog's
>tail inch at a time so it wont hurt so much.
>
>Actually, there is no reason to not raise the pitch all the way to 440
>on the first pass. If the structure is not strong enough to stand it, it
>will collapse by the time you get there anyway. Why not get the anxiety
>overwith in a hurry. After the first pull up, the pitch will drop back
>about 25% of the amount you pulled it up. If you use the full temperament
>strip method, it will drop about 33% because, but the time you come back
>to tune out the unisons, the middle strings will have settled about 10%.
>
>After the first pull up, the second pull can be overpulled by 25% of the
>amount it fell after the first pull up.  For extreme cases like the one
>you mentioned, it will take a 3rd tuning.  All of this can be done in
>one trip. Most of the settling happens almost immediately. I have done
>this procedure many times and come back a year later to find the piano
>right on pitch.
>
>Jim Coleman, Sr.
>