Some technical information related to
piano tuning is offered here. This may
include more details than some
customers want to read. However for
those who love the details, see the
information below.
Pitch, Inharmonicity & Tuning:
To fine-tune a piano, first the overall tension must be correct. If it is
not correct, the instrument may need a "pitch-raise" to establish
the correct tension and enable the instrument to hold a tuning at
concert pitch (A440). Once the correct tension is established, the
technician must make very small adjustments to each string to fine-
tune the instrument.
Each piano is somewhat unique due to something called
"inharmonicity". In addition to the full string length, which
represents the fundamental frequency, strings vibrate in a number
of shorter sections separated by "nodes". The nodes divide up
additional related frequencies that piano tuners refer to as partials.
Some musicians may refer to overtones or harmonics when
speaking about related topics. We won't present an argument here
regarding which term is correct (See Partials figure 2 below
diagramming the first 6 partials). However, piano tuners refer to
them as partials. These related frequencies of a tuned piano may
not match up exactly with the mathematically determined
harmonic frequencies due to a number of issues relating to the size,
tension, length, materials and imperfections in the steel strings. (If
you want a very short demonstration of partials/harmonics, ask me during
your next tuning.)
The "scale" of the piano, the design that includes string length,
diameter, materials, and tension, also impacts the inharmonicity
and tuning approach. The tuner must deal with the unique
inharmonicity characteristic of each piano. Therefore, the
technician does not simply match the strings to a given set of
pitches. Years ago there were some tuners who carried a set of 12
tuning forks to set the initial middle octave. Experience has shown
how small changes are needed in individual pianos to adjust for the
inharmonicity that is unique for each acoustic piano. Your tuner
assesses this, via listening to the interaction among notes and
partials. A slight variation is applied from the theoretical standard
to make your piano sound its best.