A New Tone Control Concept — or Is It?

A tone control experiment using a pot to fade between high and low capacitor values.

Understanding Guitar Tone and Volume Controls - Breakthrough Guitar

Guide to Single Knob Tone Controls – Chasing Tone

Neural control of lexical tone production in human laryngeal motor cortex

Spice and the art of preamplifier design, Part 2

Tone Control And Soft Switch Operated Amplifier - EEWeb

circuit design - Active Tone Control Hum and Buzz in Potentiometer - Electrical Engineering Stack Exchange

Op-Amps as amplifiers and Tone Controls

3band tone control using transistor

GA-600-2018 - Fire Resistance and Sound Control Design Manual PLUS