I was thinking about this last night... and wondering how you could do it. If you knew the resistance of the pot at the "sweet spot" where it cleans up the way you like, you could add a resistor of that value between the grounded leg and ground. So when you rolled it all the way down it would not completely shunt the signal to ground. If you did want the ability to shut the volume all the way off you could use a push/pull pot to kill the volume. Just brainstorming here... but its a thought.