This article is largely an expansion and combination of the concepts in R.G. Keen's The Secret Life of Pots and Rod Elliott's "Better Volume (and Balance) Controls". Specifically, using a tapering resistor with dual linear potentiometers in order to acheive a logarithmic response over the majority of the control and utilizing voicing options that the dual potentiometers enable.

Both of the methods outlined in the articles, on their own, provide results that are up to on par with conventional logarithmic pots. The tapering resistor has a fairly varying slope, an input impedance that varies a wide amount as the volume is turned, and is only logarithmic for maybe 70% of the rotation, with large errors at the ends of rotation.

A compound volume control has less overall error, but it's slope is too shallow for the majority of the control, until the very minimum where it nose-dives out.

 

WHile this trick cannot replace proper design to contain noise, it can take a quiet circuit and make it even better.In fact, this tracks so well that a low impedance source isn't required. Following a medium-impedance stage, like a simple tone control or a common cathode stage, would still work perfectly well.

Because of this more reasonable ~2:1 range of input impedance, we can voice a high pass filter with the volume control where at clean volumes there is no appreciable cutoff of bass frequencies, and as the volume increases, the cutoff moves up.

There is also potential on the treble side for voicing. By having a bright capacitor only one of the potentiometer wipers, there can be an "in-between" brightness setting.