Comment by aylmao

Very cool idea! It reminds me of how software works— you usually drag an LFO to the knob to modulate a parameter.

A few people have pointed out that the knob can act as an attenuator when it's being modulated via a jack, but sometimes the goal is space. I can also imagine a version of this that uses the same technique, but where the knob has an audio jack on it. You wouldn't need to unplug it to connect the incoming cable, and you could use the still-connected knob as an attenuator if you wanted to. This would get you the best of all worlds— maximum space, an intuitive interface, and attenuators if you so choose to have them.