A special feature of the BBCMP is that it enables the operator to split the incoming signal using the Low Pass and High Pass filters. These then allow you to apply processing (compression, limiting, expansion and gate) to each band independently.
Once each band has been processed, the following signal pathway shows you how the separate bands are then summed to produce the final output. The great advantage of processing in this way is that you have full control over the extent to which the 2 bands are processed rather than only the summed signal being processed. This means that if, for example, the low end is strong and pushing the compressor to attenuate the signal when it comes into play, in a standard compressor the higher frequencies would also be compressed at these times. With the BBCMP you can separately control the low end and leave the high end relatively unprocessed, if that is what you need, or conversely deal with the high end and leave the low end with lesser processing.
The Analog/Digital options vary the attack and release characteristics of the processor and will vary the 'colour' of the output. Switch between them to hear the difference and select what works for you. You will notice that the actual Attack and Release times are fully controllable for each band. This switch has more to do with 'colour' or 'feel' of the sound. The BBCMP does not introduce 'hiss' or 'analog noise' when in the 'analog' mode..