Pianos Are Always Technically Out Of Tune
Even a piano that sounds perfect is actually at least slightly out of tune. An equal temperament tuning system puts the same interval between each adjacent pitch on an instrument, which means that each time you move from one piano key to its neighbor, the note is going up or down by the same "amount" each time. However, tuning the piano this way-putting 12 equal parts in an octave-also means that the notes won't be perfect. They'll be ever-so-slightly off, all in the name of allowing the piano to play in any key. We've collected some awesome videos on this topic. Watch them now to learn more.
Key Facts In This Video
In the traditional western scale, the jump from one pitch to another with half or double the frequency is called an octave. (0:45)
It's mathematically impossible to tune a piano across all of its keys using harmonics, and so most are tuned with equal tempered tuning. (2:45)
Equal tempered tuning enables pianos, digital tuners, and computer instruments to play any song in any key (though they will be imperceptibly out of tune). (3:34)