Piano Has A Temper

No, your piano is not about to throw a tantrum if you don’t practice! Temper, or temperament, are terms referring to methods of tuning the piano.

In Western music, most pianos nowadays are tuned using Twelve-Tone Equal Temperament, or 12-TET. This means that the twelve notes that make up an octave — the chromatic scale — represent twelve equal frequency intervals. The difference in frequency between a C and a C-sharp, or a D-flat and a D, is the same.

The goal of equal temperament is to make different keys (C, D, F-sharp, and so on) sound equally well in tune. Seems obvious, right?

Not so fast! In fact, this simple-seeming tuning technique took hundreds of years to develop. What’s more, in order to make all keys sound equally well in tune… each individual interval must be made ever so slightly out of tune.

To understand this, let’s take a step back. A musical note, or tone, is simply a sound wave of a certain frequency. Certain combination of notes, or frequencies, sound more or less pleasant to the human ear. When a piano’s strings are adjusted to enable the pleasant frequency combinations to predominate, while unpleasant combination are minimized, the piano sounds “in tune.”

One of the earliest methods of tuning was Pythagorean Tuning. In this method, particular intervals were based on whole-number ratios (i.e., 3:2 or 4:3). These intervals are particularly pleasing to the ear, and are known as “just intervals.” Unfortunately, when one key (for example, C), is “in tune” using just intervals, other keys are perceived as being out of tune — in some cases, quite badly. Imagine giving a concert where all the pieces had to be in the key of C, because anything in the key of F-sharp would have sounded out of tune!

Why? Because just intervals cannot be fit evenly into an octave if there are only 12 tones in the octave. There’s a little extra frequency left over, called the “Pythagorean comma.”
To solve this problem, the just intervals are “tempered,” or degraded slightly from their purest form. How best to achieve this has preoccupied pianists and tuners for centuries.

A popular tuning system widely used in the Renaissance was “Meantone” Temperament. In meantone temperament, the just tuning of certain intervals was compromised in favor of others. Certain musical fifths might be narrowed (the top note made slightly flat) in order to allow the musical major third to more closely approach its just ratio. These out-of-tune fifths were known as “wolf” fifths and were concentrated in certain keys, which were sacrificed to the better tuning of other keys. Composers of the day simply avoided using the unplayable keys with wolf fifths.

During the time of Johann Sebastian Bach, Well Temperament was developed. Well temperament is an “irregular” temperament, meaning that the intervals between adjacent notes are not equal. This represented a major advance over meantone tuning, since all keys were playable without the instrument having to be retuned. However, the keys still sounded slightly different from each other, a phenomenon known as “key color.” For example, a particular key might be described as “dark” or “melancholic” and therefore be seen as more appropriate for certain pieces and less appropriate for others. Bach wrote two books of preludes and fugues to take advantage of well temperament. The title? “The Well-Tempered Clavier,” of course!

About a hundred years ago, modern Equal Temperament was developed, and it remains in general use today. Believe it or not, it was once controversial! Natural or just intonation was seen as reflecting God’s order; equal temperament, which debased all intervals for the sake of the overall effect, was seen by some as detrimental to the purity of music. Others lamented the loss of key color. Indeed, there are some purists even today who hold that music written for other temperaments betrays the composer’s intentions when played on an equal-tempered piano.

Now you know your piano’s temperament — and why your piano tuner should be given the utmost respect!