Tuning temperaments & Concert Pitch
The piano is an instrument that has fixed intonation. While a violinist or flautist can vary the pitch of notes to make them fit pleasingly within the key they are playing, this is not possible on the piano. Indeed many of these artists do learn to play scales within varying temperaments. Pure intervals, when stacked up on a keyboard, result in octaves that aren’t pure and key signatures with “howling-wolf" tones. This is a mathematical reality; thirds, fourths & fifths do not perfectly coincide. In order to accommodate the western scale, we have to compromise intervals to fit within the scale. This is what is called "tempering." The result is a “temperament.”
Modern equal temperament is the latest "evolutionary" stage in the development of the western musical scale and temperament. It is the most adaptable and allows transposition across the keyboard without affecting the character of the music played. Previous temperaments were not so flexible and were abandoned by the piano industry as newer ones were developed. That is not to say that equal temperament is musically better. In fact equal temperament is equally dissonant in all keys. Most of the famous composers utilized other temperaments which distributed the dissonance in other "unequal" ways. In fact some of the compositions obviously utilize the features of unequal temperaments for artistic effect. Equal temperament was discussed as early as J.S.Bach's time and was not thought of as necessarily desirable. In fact what was called “equal” in Chopin’s era most definitely was not equal temperament. Equal temperament is a 20th century phenomenon.
There is some merit to the argument that the temperament in which a certain piece of music was composed best represents what the composer intended. Of-course, one would have to perform a piece on a period instrument so tuned to hear what the composer heard.
On the other hand, music does reach across time and modernization. Selecting a historical temperament can limit what pieces sound good on your piano. Tuning to Kellner makes Bach and Mozart sound sweet but it also makes Debussy “grind.”
Andrew usually tunes in the modern equal temperament at modern concert pitch, A4=440 hertz for customers. In the store most of the pianos are tuned to a mild well-temperament as customers have (without prior knowledge) preferred identical pianos tuned to it over the other piano tuned to ET.
If requested alternate temperaments and concert pitches are available.
Caveat: modern pianos are designed to sound their best at modern concert pitch. Certain old pianos may have been designed around a lower concert pitch.
Re-tuning to an alternate concert pitch or temperament would typically be charged as a Pitch Correction.
To learn more about historical temperaments, you may check out these resources:
A Beginners' Guide to Temperament by Stephen Bicknell.
Provides an overview of the historical development of temperaments.
Understanding Temperaments by Pierre Louis.
Another introduction to temperaments with a more detailed explanation.
An Introduction to Historical Tunings by Kyle Gann.
Authored by a professional musician, composer & professor of music at several colleges who isn't enamored with the modern equal temperament.
Temperaments Visualized by Jason Kantor.
This site is quite helpful in answering common questions, such as which temperament a composer was likely exposed to. It provides a chart which visually demonstrates the time the composers lived and the temperaments that were then current. Clickable links provide highlights of different temperaments.