Cents in pitch raises

[Richard Moody]

My questions:
 1.) Is four cents flat too much to get a stable concert
tuning?

William R. Monroe
PTG Associate
Salt Lake City, UT

Unless you tune by machine only, it helps to know how cents
translates out to actual frequencie differences or beats per
second.  I was once asked to tune a pit piano to 441.   I
arrived with every argument to tune to 440.  Before I could
start, the head of the Musician's Union said they wanted 440
for performance but needed it to be tuned to 441 because
when the theater was filled and the lights were on the piano
went flat.  So  he figured it should be tuned to 441 since
the tuner was in an empty "dark"  and cold theater.
    Now he was talking about one cycle per second not cents.
Not having a 441 fork I  envisioned tuning sharp to the fork
by one beat per second--which I mentioned.  Then I noticed a
Korg pocket tuner lying on an orchestra member's chair.   I
asked if this was used to determine how much the piano had
gone flat.  To make a long story short we agreed to raise
the pitch when the needle of the Korg got to half way
between 440  and 441.   Since it was a lengthy "gig" I
offered to buy one, (it was $150 in 1979), and also I
demonstrated that it showed my fork went flat when held in
my hand for 20 seconds so it was indeed sensitive.

    Now the question was asked "is 4 cents flat too much to
expect for concert tuning. " Well this piano supposidly went
from 441 to 440 during the program.  That is a swing of 4
cents, (3.92).   Not all instruments respond this
much---some perhaps more,  but still the reality of concert
performance is that the piano does change pitch more or less
after the tuner leaves.
Since the advent of pocket tuners musicians can verify how
much this happens.  It also happens to instruments in the
orchestra.  Some go sharp some go flat.  These variances are
well within the parameters of intonation and the piano
varies less I think.

    If you tune for a rehersal and come back for a touch up
and the treble is "4 cents flat" to  the reference note
which has not changed, you have some work to do.   I don't
know aurally what 4 cents flat is in the 6th or 7th octave.
A spread sheet shows the freq of A6 when flat by 4 cents is
very close to 1756, or four beats per second flat from the
theoritical pitch 2 octaves above 440. (1760)
    This much difference between the rehersal tuning and the
pre show touch up on the same day would be a major concern.
I have never encountered so much so it must be a rare event.
; )     Never the less, a flat treble is more common in once
a week tunings on a piano just moved in, or in practice
rooms after the seasons change.   If you have to raise even
12 notes one beat per second in one tuning you should find
and tune these notes first and after the tuning check them
again.   You need two passes since simply checking them
takes an amount of time to qualify as a "second pass".
The less tuning you do on the second pass means you adjusted
right or the piano responded right or both.   The more
tuning on the second pass means you didn't compensate enough
or the piano responded more than ordinary.  Don't be
surprised on raising a treble "4 cents" or one beat per
second  esp if over two octaves you need 3 passes.
    But 3 passes---so what?   A pass of two octaves should
take 10 minutes the first time and even less the second or
3rd.  Tuning (raising to pitch) is like sculpture.  You chip
away till you get it right.

    By the way a one beat per second difference between 440
and 439 is close to 4 cents.  A four beat per second
difference (440-436) is almost 16 cents.   So cents
differnces vary drastically in aural terms through the
octaves.     ---ric


---ric