The simple fact is that AVRs that use room correction software and adjust the crossover frequencies do so independently of the speaker design, and this can introduce all sorts of problems, as you suggest.

If you read reviewer's comments when testing speakers, you will find that many find that the software actually makes the system sound worse in many cases due to various effects on phase and distortion, and they end up disabling it to get the best sound quality.

Speaker systems can be designed to have correct time, space and phase alignment; all Vandersteen designs are done this way and this results in a fundamentally superior sound quality to my ears. It is more expensive to do properly, but the oats are always better before they go through the horse.

I happen to be one of those dinosaurs who maintain that a good 2.1 system is better-sounding than a 5.1 system in any case, so there is probably no hope for me.

I have never been crazy about the 5.1, and in every case ended up going phantom 4.2. Ok, I'm 56 got that over with :)

2.1, 2.2, 2 and 4.1 or 4.2 have always seemed to fit within a more balanced spread from what I have experienced even though many go for that center boost. For myself those odd numbers in setups always stick out as such. I would also agree that the 2.1 is a special setup that can produce some serious magic as you learn your room and speaker blends.

I only use caps & resistors on my mains BTW. Inductors on mains is a no no in my designing these days. The sub is a little different, and for that I've always enjoyed the Paradigm X-30 to do my dirty work.

I might also add, for my higher end models of speakers the decision to go port or portless is decided in the listening room itself.

michael green
MGA/RoomTune
http://tuneland.techno-zone.net/