TECHNICAL BULLETIN #1
PITCH RAISING
(c) 1992 The Piano Technicians Guild, Inc.
Your piano, just like every piano, is designed to sound its
best when tuned to A-440 (the A above middle C vibrates at 440
cycles per second), the international pitch standard. It has been
designed to perform at a specific tension, and when strings
stretch beyond, or drop below this tension, pitch adjustments are
required to bring it back to A-440. It's important to remember
that maintaining your piano at standard pitch allows you to play
along with other instruments which are all designed to this same
standard. Through neglect, pianos may deviate from this standard,
making them unsuitable to play with other instruments and causing
them to lose market value. In addition, lower pitched instruments
can compromise the pianist's ear training.
It's important to note that pianos do not go flat or sharp
uniformly. Some strings will invariably change more than others.
IF I HAVEN'T HAD MY PIANO TUNED REGULARLY, HOW CAN I GET IT BACK
IN GOOD PLAYING CONDITION?
After years of regular use, your piano may have fallen
silent when the family member who studied music moved away from
home. Though your home is no longer filled with music, it's
important to remember your piano is still a living, breathing
thing. Its wood continues to expand and contract with seasonal
changes in temperature and humidity, and the string tension also
fluctuates accordingly. If your piano has gone without tuning for
an extended period, its pitch may have dropped far below the
pitch at which it was designed to perform. It may require a
procedure technicians call a "pitch raise."
WHY HAS MY PIANO BECOME OUT OF TUNE?
Changes take place because your piano's overall pitch is
dependent upon changes in the relative humidity. In some
temperate regions of the country, the relative humidity increases
in the summer resulting in a higher moisture content in the
soundboard and a higher string tension (pitch). In the winter,
when heating systems dry the air, the soundboard loses moisture
and contracts, causing the pitch to drop. The drop in the winter
tends to exceed the rise in the summer, so the net result is a
drop in pitch each year that the piano isn't serviced. In some
parts of country where the cold season is exceptionally long,
the annual drop can be considerable. In other parts, mild winters
combined with dry summers cause the cycle to be reversed. You
can, however, greatly increase the stability of your piano's
pitch by maintaining a relatively consistent humidity level in
the room.
WHY IS A PITCH RAISE NECESSARY?
When the tension of each string on a piano is raised back up
to pitch, the additional load on the piano's structure causes the
pitch of previously adjusted strings to change. The only way to
achieve a fine, accurate tuning on a piano is to have the tension
of all the strings so close to their proper place that altering
the tension of one string would not affect the others.
Therefore, a piano must already be fairly close to standard pitch
in order to be finely tuned.
WOULDN'T IT BE EASIER TO JUST TUNE THE PIANO TO THE LOWER PITCH?
Tuning to anything other than the international standard of
A-440 is seldom appropriate. If a very old piano has been
allowed to remain appreciably below pitch for a long time, some
strings may break if the piano is restored to A-440. Your
technician will advise you as to whether repeated tunings will
correct the problem, or if the piano should be completely
restrung or rebuilt.
If a piano has dropped in pitch, the drop will not be even.
The middle (tenor) section of the piano usually drops most along
with the high treble section. The bass section tends to drop
least. Consequently, a piano that is tuned to a pitch that is
below the international pitch standard would have to have
significant adjustments made to the tension of every string,
resulting in an unstable tuning. It's much more reliable to bring
the piano up to standard pitch and then to proceed with fine
tuning.
HOW FAR FROM THE STANDARD PITCH MUST A PIANO BE BEFORE A PITCH
RAISE IS NECESSARY?
Pianos that have been subjected to severe changes in
humidity routinely need pitch raises before a fine tuning can be
achieved. For example, if A-440 has drifted only two cycles per
second to A-438, a separate pitch raise is advisable. Most
recreational musicians would want to have their pianos tuned
before the pitch drops that far. Even if you aren't bothered by
a slightly out-of-tune piano, it's best to tune the piano on a
regular basis to avoid tuning instability and the extra cost of a
pitch raising procedure.
Like your car, your piano is a major investment which
deserves to be protected by regular servicing, which can head off
preventable problems in the future. But most importantly, your
piano will sound its best and give you and your family the most
pleasure when it is tuned regularly and kept in proper playing
condition.
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The preceding article is a reprint of Technical Bulletin #1
published by the Piano Technicians Guild, Inc. It is provided on
the Music/Arts Forum as a service to piano owners. Additional
titles in the series will be uploaded in the future.
The Piano Technicians Guild is an organization of piano
technicians in the United States and Canada. Registered Piano
Technician (RPT) members of the PTG have passed a series of exams
administered by their peers, demonstrating their mastery of all
facets of their chosen craft.
For a copy of this or other PTG Bulletins and Pamphlets, or a list
of RPT members in your area, contact the Piano Technicians Guild,
Inc., 3930 Washington, Kansas City, MO, 64111-2963. Phone: (816)
753-7747 FAX: (816) 531-0070 E-Mail on CIS: 75032,3711
[8-24-94 edo]
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