Shelves

Mutable Instruments' voltage-controlled EQ filter, 18 HP: a high-shelf, two parametric and a low-shelf section, every frequency and gain under CV, with the two parametric filters' HP, BP and LP outputs.

Key features

• Four sections sharing the same ranges: frequency 20 Hz to 20 kHz (CV 1 V/Oct), cut/boost -15 to +15 dB by knob, down to -40 dB by CV (3 dB/V)
• Two parametric sections with Q from 1 to 10 by knob, much higher with CV
• Global FREQ and GAIN CV inputs offsetting all four sections at once
• The parametric sections are full state-variable filters: individual HP, BP and LP outputs for each
• Analog, DC-coupled signal path; output clipping lamp; all CV inputs handle audio-rate modulations
• Made from 2015 to April 2021; the design is open source