Otl's with AvantGarde Duos?

Nope, look into Lamm ML 1.1. Avantgarde's sing with Lamm's.

My semi useless two cents. You should really audition OTLs before going on reputation. They have a sonic signature which is hard to describe but most definitely present. I have horns but not Avant Garde everyone said use low power SETs the horns are so efficient. I didn't like the SET sound for the music I intended to play on that system. That being said I have heard OTLs which I thought were outstanding. I would be careful with the OTL and horn you may encounter a overkill and thus fatuiging upper register and a lack of good bass.

FWIW, we have lots of customers running Avant Gardes- Unos, Duos and Trios. One of the first reviews of the S-30 was on Unos. The combination definately works. Bass is of course no problem.

Naturally, since I am a manufaturer, you have to take any comments from me with a grain of salt. Your best shot in cases like this is always to go through the effort of audition. No amount of advice from others is really going to do it. You simply have to hear it for your own self.