1, the pitch of sound, that is, the intensity and amplitude of audio.
2, the tone of the sound, that is, the frequency of audio or the number of changes per second.
3, the timbre of the sound, that is, audio overtones or harmonic components. Judging the sound quality of an audio product is mainly to measure whether the above three aspects of the sound have reached a certain level: whether the pitch has a certain intensity relative to a certain frequency or frequency band, whether the amplitude of each frequency point is uniform, balanced and full at the same volume within the required frequency range, and whether the frequency response curve is straight; And whether the pitch of the sound is accurate, which not only faithfully shows the original characteristics of the frequency or composition of the sound source, but also is a Hong Kong brand sound with excellent quality.