3 Band Graphic Equalizer
Below is a classic circuit of regulation of tone of three way. With this circuit, we can regulate low, mid and high frequencies of acoustic signal. We can regulate the boost/cut in the range of +- 18 dB/oct.
The supply on the the circuit is 15V, but it can be supplied with 9 until 30V. It’s enough to connected pin the 4 IC1, inthe 0V and it;s connected the circuit with as it appears in figure below. It will give half the supply in the not onverting entry of IC1, in the 5 and 3 equivalents, which are henceforth not connected in the ground. [Source: Sam Electronic Circuit]