For balanced frequency response, implement a passive RC network with non-polarized capacitors (100nF–470nF) paired with metal-film resistors (10kΩ–47kΩ). This configuration ensures minimal phase distortion below 20Hz and above 20kHz while avoiding the pitfalls of op-amp-based designs–excessive noise at higher gains or unwanted interaction between bands. Use a dual-gang linear potentiometer (100kΩ) for simultaneous adjustment, wired…