Thank you. Basically, if I can't figure it out myself, it ain't gonna happen! So, I'll do some research. Appreciate your reply!Any 8channel DSP will do.
„Cheap“ new options are the Dayton DSP or the Rockford Fosgate DSR1.
Higher on the list, but also more expensive and advanced are JL Audio TwK88, all Helix DSPs, all Mosconi DSPs, Audison and others.
If you want to buy one look out for an installer with experience in setting things up and go with their recommendation.
Or learn it yourself, which will take some time. You need a USB mic for that, the most popular choices are the MiniDSP UMIK microphones.
Software you need is RoomEQ Wizard (short: REW). This software can be intimidating at first due to all the options, but there are literally thousands of how tos regarding REW available. It just takes time to learn on how to get repeatable and consistent measurements, learn the DSP software of choice and so on.
So letting an installer do all this is totally viable, if the installer knows what he is doing.