The Empeg's equalizer has two modes: Two-channel mode and four-channel mode.
In the two-channel mode, you get about ten bands each for the left and right channels. In the four-channel mode, you get only about five bands per channel, but you can control front and rear as well as left and right.
I once asked: Why even bother with left/right EQ? Wouldn't it make more sense for a car audio product to have ten bands each for front and rear instead of left and right? The answer was: The off-the-shelf DSP that we use to perform the equalization simply works that way, and we can't change it.
I was thinking about it... and my new question is... why not? Aren't the designations of front/rear left/right mostly arbitrary? Why can't you just physically (at the circuit board) rewire/rename the inputs and outputs to/from the DSP to get ten bands each for front and rear? You know, fake the DSP into processing the audio channels in your order rather than its predefined order?
I don't understand how the DSP fits into the architecture of the unit, so I'm probably asking the wrong question. Enlighten me.