stretching

[Scott Thile]

Avery Todd writes:

>   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.

I have herd "stretching" used to mean two different things:
   1.  The necessary compensation for inharmonicity in tuning pianos. For the
laymen, inharmonicity is present in all pianos because of the high string
tension
and refers to the partials or harmonics being sharper then their theoretical
frequencies. Because of inharmonicity for an octave to be true, or beatless,
the top note in the octave must be slightly sharper then double the fundamental
frequency of the lower note.
   2.  I have also heard "stretching" used to describe the practice of
tuning sharper
than the inharmonicity requires us to tune, so that the octave is expanded,
no longer
completely pure or beatless. I believe most tuners expand octaves slightly,
and I
know many very respected concert technicians that expand octaves or
"stretch" there
tunings considerably farther than I am comfortable with.  Their tunings
sound great
in context but will show a very significant beat in the double octaves. The
amount of
stretch becomes subjective and I think if done well it is subtle and even
transparent
to the pianist. This type of stretch will tend to make a piano sound
slightly brighter but
should not be used in place of voicing. Whatever "stretch" is used must be very
consistent to work well.

>1) is this a common and accepted tuning practice?

Yes it *is* common practice, the degree of stretch will very between
technicians and
sometimes even with the same technician. ( I "stretch" my concert tunings
more than
other tunings, and also "stretch" more for certain artists).

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

Yes,  but most good tunings are "stretched" to a degree, so it becomes a matter
of how much.

>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?

Yes, I think so.  The problem is the pianist can only know what they want
 when they hear it, and I think they must hear it in context (i.e. an entire
tuning)
So any experimenting as to a "custom" degree of stretch could be time
consuming and therefor expensive,  It will also change for each piano
because of the factors involved, and it will likely vary with the repertoire
to some
extent as well.

It is an interesting subject.....

Scott
Scott E. Thile, RPT
Piano-Instrument Technician
Department of Music,Murray State University
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