Simplified circuit when boom is grounded

The center tap of the precision potentiometer is connected to ground. When the sliding arm of the potentiometer is at the midpoint of the potentiometer, the sliding arm is grounded.
Assuming that the number of equalizer segments is 1, the circuit can be simplified as Figure 1-94. Since the operational amplifier can be regarded as an ideal amplifier
, its voltage gain is equal to the impedance ratio of the feedback branch.
    In practical application circuits , the equalizer is often not one segment but one segment, such as 5 segments, 7 segments, and 10 segments. . When the sliding arms of the potentiometers
of these segments are all in the grounding position, it is equivalent to ri in Figure 1-94 becoming ri/yue, and r2 becoming r2/