Musically, different octaves are determined and marked by "big N group" and "small N group". The first sound of each group is C, and the last sound is B, which is the arrangement of the landlord, not the lowest A and the highest G.
The values of elements constituting an audio circuit must satisfy the following relationship:
Compared with the related resistances, the capacitive reactance of C 1 and C2 is small enough at high frequency and large enough at middle and low frequency. Capacitance reactance of C3 and C4 is small enough at high frequency and intermediate frequency and large enough at low frequency. C 1 and C2 can let high-frequency signals pass, but can't let low-frequency signals pass; On the other hand, C3 and C4 allow high-frequency and intermediate-frequency signals to pass, but not low-frequency signals.
Baidu encyclopedia-tone