One of the technical areas of piano tuning, the
temperament, is described below. This is more
information than some customers want.
However, there are some inquiring minds who
love the details.
When a piano has been tuned using an equal temperament, the
octave intervals have been divided into smaller steps, each having
equal frequency ratios between the adjacent notes. These are the
smallest intervals in the tempered scale that is commonly used in
modern music. Each of these intervals represent 1/12 the width of
the octave and are referred to as a semitone or half-step. In the
modern tempered scale, the frequency between each interval is
perceived as being the same distance apart.
Before learning about the tempered scale, I wondered why classical
music often lists the key. For example "Piano Concerto in A minor"
or "Chopin's Piano Concerto in F minor". Why did these classical
composers care what key? The answer lies in the historical
temperaments of that era. There are many references to the
tempered scale, its history, and examples of the historical
temperaments. Importantly, there is no such thing as no
temperament (See Temperament Figure 1) in a piano tuning scale.
To accommodate the imperfections in the scale, some
"imperfections" must be built into the tuning. Various historical
temperaments cause a composition to sound different depending
upon what key it is played in. If played in a modern equal
tempered scale, the difference may be undetectable other than the
relative pitch reference. But in the original classical temperaments,
the difference is quite significant.
You can find considerable information on the historical
temperaments. If you want to hear the difference, you can search
on-line for "same song in historical temperaments" and you may
be able to listen to recordings for comparison. Below is a very
simple diagram to show why there must be a temperament for the
piano scale. If you search for more information, you will find
enough to keep you reading and listening for a while.
The Tempered Scale:
The piano temperament is a term in piano
tuning that refers to the intervals between
notes on the musical scale. Every pitch
can be derived, electronically or aurally,
from a relationship with a chosen fixed
pitch source. One of the first steps in
piano tuning is to set one string per note
of at least one octave to the desired
relationship with each other. This
establishes the temperament (basis) for
tuning the remaining notes on the
instrument.