Guidance for my new 7.1-System needed (Center, backward-Speaker)

[Blitz]

I am currently planning a new house and want to have a 6*7m room dedicated to Stereo and Homecinema.

For Stereo the solution is clear: I have designed a mighty line-source with 18 4" eton chassis and 12 fountek ribbon which give me a 2,2m high loudspeaker with fantastic resolution and dynamics. The subwoofer is as well clear: a horn in the corner of the room.

Now comes the tricky parts:

Center:
- How big does it need to be ? Is one ribon and two 4" enough or does it have to be four 4" Etons or even more ?
- Should I design for two centers ? One close to the ceiling another close to the ground so that the screen (3m width) is surrounded suffieciently ?

Side & Backwards speaker:
Are small satellites suffient like one ribbon and one 4" Eton or do these speakers need to have as well a lot of dynamic reserves, so that I need at least 2 4" eton per Speaker ?

[SSassen]

Ideally all your loudspeakers should be similar as per the DTS, DD5.1/6.1 EX spec they all carry full range signals, do not make the mistake of using 'simple' rear speakers. I'd opt for a acoustically transparant screen and mount the center speaker behind it. dead center. For all speakers I'd use small chassis, and a small baffle to enable a broad sweet spot, with your proposed line array this will be an issue. I guess you'd like others to enjoy good imaging as well not just you sitting exactly in the middle.

A configuration with two Eton woofers and a ribbon tweeter in MTM, or rather D' Appolito configuration would be a good starting point. I've just finished simulating, prototyping and measuring (MLS) a loudspeaker for just this purpose, and have started construction. These feature two 5" Seas L12RCY woofers and a Seas 1" H1212 tweeters. They will be supplemented by a subwoofer due to their roll off after about 60Hz.

Best regards,

Sander Sassen
http://www.hardwareanalysis.com