I can't stand using buttons to control volume. It's simply unintuitive to control a limited absolute value using relative controls (at least in this case). There are keyboards with built-in dials, but my Razer Blackwidow Chroma doesn't have one. However, it does have a USB passthrough port...

I took a Digispark USB Microcontroller, soldered a 5k Ohm potentiometer to it, added a plastic knob and wrote some simple lines of code... and it works! It can even be used as a MIDI controller by altering the software.