I use passive subs connected to component amps that do not have independent level control and I would like to control the levels between the lfe out and the amp input. It seems I could accomplish 4 channel level and eq with a dsp device or possibly just a rack line splitter such as this http://www.behringer.com/EN/Products/MX882.aspx
Turning the knob is an easy way to adjust levels. How hard is the mini dsp device to setup and does it require any fiddling to keep the settings loaded in it? Im guessing you adjust levels in an app and then flash it over usb. What if the power goes out to the dsp?
Pros and cons for rack splitter vs dsp device? Of course eq is obvious, any others?
The miniDSPs retain their settings an extremely long time even when unpowered. Setting up is indeed by flashing over USB although one can change settings in "real time." One can add an analog level control to the miniDSP but level changes are primarily done with the app. Another use for you might be implementing a HPF for your subs.