Hello everyone,
as I write in my presentation I like to build loudspeakers since many years but until now I have worked only with closed box and bass reflex, never tried the OB way.
Actually I'm thinking at my first OB project but I'm unsure about the design and the drivers to use: in my mind there are two designs, one using two 15" + two 6" midrange + two tweeters (MTM configuration with one tweeter in the back) and one using four 12" + two 6" midrange + two tweeters (same configuration), here is the draft:

Left one is 180cm (6') tall, right one is 210cm (6' 11") tall, space behind the loudspeakers will vary between 1 and 3 meters (3' 3" and 9' 10") due the oblique ceiling.
For budget reason speaking about the 15" I'm thinking about Eminence Beta 15, still looking for the 12".
I'll initially drive those dipoles with my bi-amp capable HT amplifier, given for 120Watt for channel at 8 ohm (cannot go under that impedance), using passive crossovers... in the future I'll move to a multiple amplifiers setup and, possibly, active crossovers but yet to decide, anyway I'd like to build a loudspeaker that is good for my actual setup as well as for my next one without changing all the components.
What I do not consider is the following:
- coaxials drivers
- full-range drivers
this is a prerequisite.
That said, as I am a completely newbie about OB loudspeakers I'm here to ask you if this kind of setup is a good start or if you see any critical points.
Thank you in advance!
Best regards
Angelo