Simplified equivalent circuit of integrated op amp tone control circuit (b)

Use the relationship obtained from the above analysis to design and calculate the tone control circuit, in which Ai is the buffer amplifier
stage to reduce the burden on the previous stage output.
The low-frequency turning frequency of this circuit is 30Hz, the high-frequency turning frequency is 1kHz, and the control range is ±20dBo.
    Using an operational amplifier can not only design
a tone circuit with high and low bass control functions, but also design a tone circuit
with high, medium and bass control functions. Control circuit , the actual circuit is as shown in the figure