My my, how times change... Did you know that the piano's tuning has changed? (Drastically!) Bach in the 1600's, the keyboard was tuned primarily in one key. If you played in closely related keys (keys with just a few more sharps or flats) the music would sound pretty much in tune, but if you ventured to distant keys, the neighbor's dog would begin to howl...

Here's why:

There is an interval in music called the "Perfect 4th". It is the interval between the root and the 4th note of the Tetrachord. (Zowie! That's a big word! Get our piano lessons course and you'll understand it...)

Long ago, this interval used to be tuned "Perfectly". (hence the name) However, if you start on C, and then go up a 4th ("F") and tune the F perfectly, and then go up a 4th and tune the Bb above that perfectly, and continue going up a 4th (tuning each interval perfectly) until you come back to C, this new C will be quite a bit out of tune with the original C!

The same is true for Perfect 5ths!

So, the tuners of long ago used to tune keyboards (Clavichords, Harpsichords, etc.) in one key, tuning all the 4ths and 5ths in that key perfectly. If you wanted to play in distantly related keys, just keep a few extra Harpsichords in your living room, all tuned in different keys...

Then came along a tuner who said "Let's compromise"

He tuned all the scale tones equally "out of tune" just enough so that as you traveled up the keyboard by not-so-perfect 4ths or 5ths and came back to your original starting note, you were still in tune

J. S. Bach said "I can dig it!"

He could now play his keyboard in any key he chose! He immediately wrote "The Well-Tempered Clavier". This was a landmark piece in the world of classical music, with a prelude and fugue written in every key! This new method of tuning is called "Equal Temperament".

Webster's definition: "...the process of slightly modifying the musical intervals of the pure scale to produce a set of 12 equally spaced tones to the octave which enables a keyboard instrument to play in all keys"

Want to whack out your ears?

If you've got a keyboard that can play different tunings, select "just tempered". This will give you an idea of what music sounded like in Bach's day. To us, it sounds really out of tune. In truth, it is out of tune (the purists will sue me for saying that) because Equal Temperament produces equal spacing between all twelve notes. The 4ths and 5ths are not "perfect" anymore, but spaced just enough to sound great!

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