> For the subwoofer, I'd probably use a Theater Series three π speaker, provided you're not running a tube amplifier for this channel, which I'm assuming you're not. You can omit the tweeter and crossover since you'll be using it as a sub. This is a good match for your other speakers, both in performance and in size. It's not very large, and it will hit 30Hz pretty well, particularly with a little EQ.

My room is 5m*8m*3m, i am using solid state (onkyo) for HT.
I have also one free corner: wold be corner horn sub
a better solution ?
Could you send me also the plans for the sub ?

Thanks again,
Vladimir