[Geoff130]

Thanks but I don't think these are programmable, there are ten BA14741 quad op-amps, three or four TA8233H power amps depending on the model, a TIP32C transistor to switch the power on and off and 7 small signal transistors scattered about. One op-amp buffers the four inputs and splits them between the four channel filters and the sub woofer drive which combines them into another op-amp that forms a low pass filter.

I've been toying wit the idea of using the BMW DSP amp but that will need more wiring to the doors and they don't seem too impressive on the BMW forums, not to mention expensive.