[mbayaq1]

I would really like to put in a variable crossover control for the subwoofer as well as a volume knob for the sub that actually mutes it and allows me to control the level of the sub much more accurately.  Can these things be done?

[WerTicus]

yeah no doubt you could.. but i have never seen the inside of a logitec speaker so i couldnt say HOW

but probably a variable resister will be involved in its creation

your going to want to know a fair bit about designing attentuation circuits and your going to have to figure out where they go.