Stretching

[RndyPotter@aol.com]

Dear Avery;

  Regarding your questions on "stretching", and the questions asked you by
piano instructors at UH?
  When I started tuning 20 years ago, "stretching" was a commonly used word,
but not so anymore. It developed a poor connotation, probably well-deserved,
and probably for a number of reasons which I will not go into at this point.
  However, the word "stretching" seemed to convey that thought "we", the
tuner-technician, were doing something to the tuning to manipulate it in some
way, rather than tuning the piano to match itself.
  If an automobile tire is designed to be inflated to a certain pressure, say
35#, when it was at a certain load on a certain car, it would be appropriate
to fill it to 35#. If, however, someone wanted to use the tire for a
different application, say riding on sand dunes, they might overfill it,
maybe put 40-45# in it, so it would be fatter and not bog down in the sand.
On the otherhand, in the winter some say to lower the pressure, maybe to 25#,
in the snow, so more tire will contact the snow and give better traction.
Neither, so say automotive and tire specialists, works well, if at all, but
people say it none-the-less.
  In the opinion of many piano technicians, "stretching" is the same in
overinflating or underinflating the above tire.
  As piano tuner-technicians, we are trying to tune the piano in such a way
as to "match" our tuning of the strings to the optimal scaling present in the
piano's design. In most cases, the closer we can match that, the better the
piano will sound.
  There are exceptions. Franz Mohr, who served as Horowitz' piano technician
for 34 years and recently retired head of Steinway's Concerts and Artists
Division, taught us to begin tuning the treble notes just a little bit
sharper than we normally might, beginning about E56, but making the fifth
(A49-E56) just a little bit more pure, thus raising the notes to where the
octave was about as wide as possible and still remain pure. (This sped up the
10th in a 3rd-10th test of the octave.) It resulted in what we call something
closer to a 4:2 octave, rather than the 2:1 octave we most often tune in the
temperament section of the piano.
  Measured with an Accu-Tuner, we would find that C88 would end up maybe
10-15 cents sharper than if we had not done that.
  Many artists demand it, as they believe it brightens the sound of the upper
treble, causing it to carry better. It works well on many pianos,
particularly good quality grands, such as most Steinway grands, as you noted.

  But, many technicians have also found it does not work as well on certain
other pianos, which may include most uprights, and pianos with much lower
"inharmonicity quotients" designed into them. (And with pianos that were
poorly designed to begin with, or are very old and their strings have lost
their elasticity, become brittle and do not make such a good sound anymore,
anyway.)
  Sometimes a piano will take a little bit of "stretching" in the octave
well, just as some tires will actually work better on sand if they are
overinflated, or grab the snow a little better if they are underinflated. An
old, dried out tire, though, will blow up if overinflated for sand us, or
crack and break if underinflated for use in the snow. Also, depending on the
vehicle the tires are installed on, overinflated tires may now be so large
they will rub on the fender. Generally speaking, just as properly inflated
tires in good condition work best for the purpose for which they were
designed, pianos in good condition work best when they are tuned so that the
tune most closely matches the inharmonicity designed into the scale.
  While I believe it is not uncommon for piano technicians to tend to tune
the upper notes more sharp than 2:1 octaves (indeed, the new, 1995, designed
FAC scales Dr. Sanderson recently developed and now installs in all current
SATS, or those which they upgrade, do just that), competent piano technicians
do not think that they should do this to all pianos - simply because it is
not right for all pianos, and does not work well on all pianos.
  Some pianos have a very low level of inharmonicity present in their design
and/or manufacture, and will not take much. On some pianos, an octave more
than a cent or so wide will have a beat in it. On others, any less than three
cents wide will be too narrow, and 10th will be slower than the 3rd in a
3rd-10th octave test. Knowing what a piano can, and must, have in the way of
octave width ("stretching") is something that comes with training and
experience and, once learned, is one of the many "tools" we carry around and
use as we service instruments. Some of our tools are made or wood and steel,
but proper techniques and knowledge are just as much "tools" of our
profession as are tuning hammers, mutes and regulating tools.
  Some people (all of us at one time or another) get a good idea, or learn
something from someone else, find that it works well in a certain situation,
and then go apply it to all pianos they work on. As your piano instructor
professors have realized, what works well on your Steinway S does not
necessarily work on other pianos.
  Like all the many techniques we use in tuning, repairing and regulating
pianos,
  I suspect the "wild tones" you are hearing are octaves that are stretched
so far they have a beat in them.
  1) Yes, used properly, raising the pitch of the upper notes as you ascend
up the scale is a "common and accepted tuning practice", at least if the
celebrated technicians at Steinway know what they are doing.
  2) I pointed out some of the pros (if it works, if it makes the piano sound
better, if the piano will take it, if the technician knows what they are
doing) and cons (if the piano's scale design will not allow for it, if the
piano is old and the strings have lost their elasticity, if the tuner does
not know enough to use this as a "tool" properly - including when to use it,
and when not to use it). I am sure there are others, and we will be seeing
them posted as others lend their knowledge and expertise to your question.
  3)  And finally, most definitely YES to the question "and, more generally,
are well-trained tuners expected to be able to employ a variety of tuning
techniques (methods, styles--those terms again!) to suit the ears of an
individual player?" If they are not "able to emply a variety of tuning
techniques", then they are not very "well-trained" are they?

Randy Potter, R.P.T.

P.S.  It may seem this is a delayed response - the net ate its original
attempt to send. Original 12-10-95. Resent 12-25-95.

The following is Mr. Avery's original letter:

>   I have been asked about the stretching process by a teacher on the piano
list. I answered as best I could, but am wondering if someone out there
could answer better, bearing in mind this is a non-technician. Here is the
post.
RE: I have recently had firsthand exposure to a tuning technique (method,
style?--Idon't know what to call it) that "stretches" the intervals in the
upper range of the piano.  This is supposedly done in such a way that the
piano is still "in
tune."  It has the very pronounced effect (in the pianos that I have heard)
of brightening the upper register considerably.  On some pianos this effect
is
very dramatic--it sounds like the piano has been voiced up in that register.
However, in some instruments it seems to have the effect of creating (to my
ear, at least) certain "wild" tones (again, my vocabulary does not suffice),
that
is, notes that I can't confidently call out of tune, but which nonetheless
have a
grating or at least non-uniform tone quality to them.  This is something that
is definitely independent of voicing.
My questions are:

1) is this a common and accepted tuning practice?

2) are there accepted pros and/or cons to this manner of tuning?

3) and, more generally, are well-trained tuners expected to be able to employ
a variety of tuning techniques (methods, styles--those terms again!) to suit
the
ears of an individual player?

Thanks in advance for your response!

ALSO:
   his tuning sounds somewhat strange to some of us.  It's hard to pin down,
especially since none of us on the piano faculty can really pinpoint what the
issue is.  I'm not sure even where I stand. I was thrilled when my tiny
Steinway S suddenly had a brilliant upper register after a mere tuning. It
was really astonishing.  But not all pianos seem to respond as well. I'm just
curious to know if there is some kind of consensus and or established debate
in the technician's community regarding this.

****************

   I hope this subject hasn't been beaten to death before I got on the list.
If so, I will understand. But if anyone would like to comment on his
questions,
I'll be glad to forward your comments.
   Thanks again for your help.

Avery Todd, RPT
University of Houston
atodd@uh.edu