Advice on Adjustable Tone Circuit

[TonyAme]

I've been using this audio output circuit for the Arduino Nano Auduino Synth, and for the Teensy Audio Shield. Looking for advice on a possible adjustable tone circuit. Maybe replace R11 with a pot? Any advice/suggestions/comments would be appreciated.

Sincere Thanks,
TonyAme

 

[TonyAme]

In case anyone else is following this thread, I have one possible solution for a tone control added to the above audio output line schematic;
I know volume controls are usually log type, however I have found the linear to sound better.
(C15 will be determined via experimentation)))))0000))))))000

Thanks.