SHELVES /4 channel EQ

Github - BOM

Features

Controls

The low-shelf, high-shelf, and parametric sections all share the same control ranges and scales:

• Correction frequency range: 20 Hz to 20kHz.
• Correction frequency CV scale: 1V/Oct.
• Cut/boost range: -15dB to 15dB (knob), -40dB to 15dB (CV).
• Cut/boost CV scale: 3dB/V.
• Parametric correction Q: 0.5 to 20 (up to 1000 with external CV offset).

The global frequency offset and cut/boost CV inputs affect all sections.

Outputs

The two parametric sections are realized with state-variable filters with individual BP, HP and LP outputs.

Specifications

• Analog, DC-coupled signal path.
• Input impedance 100k (25k for the global frequency and gain CV inputs).
• All CV inputs handle audio-rate modulations.

Code (AVR projects): GPL3.0.

Code (STM32F projects): MIT license.

Hardware: cc-by-sa-3.0

By: Emilie Gillet (emilie.o.gillet@gmail.com)