According to international regulations, the vibration frequency of a group of small words a 1 is 440Hz, which is called "standard sound", so the frequencies of two adjacent sounds should be 4 15.30Hz and 466. 12Hz respectively. In this way, the frequencies of A and a2 are exactly 220Hz and 880Hz, that is, the frequency difference between two adjacent groups of homonyms is twice.

The frequency of the standard sound a 1 is 440HZ, and the frequency of the octave a2 above it should be 440 Hz× 2 = 880 Hz. For another example, the frequency of standard note a 1 is 440HZ, and the frequency of octave A below it should be 440 Hz ÷ 2 = 220 Hz. This kind of accurate pitch calculated by objective mathematics will make people feel that the high pitch is low and the low pitch is high, which can't satisfy the live music.