2006-12-19 08:52:26 · 4 answers · asked by Random Precision 4 in Science & Mathematics ➔ Physics
If a note is 440 Hz (A above middle C), 880 Hz would be the note an octave above (A two octaves above middle C) and 220 Hz would be the octave below (A below middle C).
The relationship is geometric (doubling/halving) rather than linear. An octave up is double, an octave down is half.
2006-12-19 08:55:58 · answer #1 · answered by Puzzling 7 · 3⤊ 0⤋
An octave indeed spans a frequency range from half the frequency to the whole, or from the whole to double the frequency.
In the well tempered tone systen, this span is somehow divided into 12 steps to create all our 12 half-tones in an unnatural mathematical but easy-to-transpose way:
Take the frequency of one tone and divide it by or multiply it with the 12th root of 2 (=1.05946309435929526456182529494634... ) and you'll have the frequency of the half-tone immediately next to it. Do this 12 times and you'll have exactly half or double the original frequency, which is 1 octave lower or higher.
About 440 Hz: Many tuning forks create this A, but 444 Hz is also used as A by orchestras (and there are other slightly different A tunings used).
Extra information:
Middle eastern music knows tones in-between our half-tones, the so-called quarter tones, of which there are several slightly different versions in Egypt, Turkey, Syria and Iraq. Most of us cannot hear those quarter tones because we are not trained to hear those, or we may think that those are a little false, but those are really meant that way.
2006-12-19 19:57:49 · answer #2 · answered by Duliner 4 · 0⤊ 0⤋
Double frequency considered from any start note
Th
2006-12-19 17:40:19 · answer #3 · answered by Thermo 6 · 0⤊ 0⤋
I believe it's half/double the frequency depending whether you're going down or up.
2006-12-19 16:55:46 · answer #4 · answered by feanor 7 · 2⤊ 0⤋