For the longest time the market didn’t offer much in the multi channel DSP market. There were $1000+ 2×6 and then 4×8 units that were $3000+. Recently that situation has changed which is good for those of us who want separate control of each speaker in a sound system. Anytime you link speakers together (either at the amp or at the DSP output) you’re giving up the ability to mute, control and optimize each speaker. How does one do a system component check if you can only mute / unmute a group of speakers?
minidsp has a few offerings that allow for some interesting possibilities when it comes to home and even professional speaker processing.
Each unit requires a software plugin to allow it to function. Fortunately the plugins are inexpensive and provide a lot of processing functionality.