Adding Home Theater To 2 Channel System


I have a two channel system that I am very happy with located in a dedicated listening room.  I am considering how to add home theater without giving up the two channel sound that I enjoy.  My main speakers are Avantgarde UNO’s (horn speakers - 18 ohm, 108 db sensitivity). Avantgarde does not make a center channel speaker.  I assume that I will have a problem matching any box speaker center channel speaker with the Avantgarde - my worry is incoherent sound.  Is this something I should worry about?  Are there center channel speakers that might be a good match (I have been unable to find any obvious candidates ohm/sensitivity match)?  Is it likely that I will need to find a new set of front speakers from the same brand as the center speaker?

The rest of my setup: Pass Labs XA 60.8, Audio Research Ref 6 preamp, SME 20/2 turntable, Lumin x1 streamer, Ayon CD player, REL 812/S subs (2)
chilli42
Good to hear. 
If you end up trying rears again just use any old speaker you have sitting around or get something cheap.

 timbral matching the rears is a waist of money unless you are really into it. 

Highend rears is a waist too. If you run high end rear speakers you will feel obligated to power them right and use good wire etc, and it all ends up not being worth it. I think for 99.9% of us we would rather spend that money improving our two channel. 
A screen is the best way to go. If you really want the least possible compromise use an acoustically transparent screen, one designed to have speakers behind it. This way you can put whatever acoustic panel you want behind the screen and it will still work. Or for more money a powered screen you can raise and lower, but those come with their own set of problems. 

In any case, done right you will wind up with four subs in a DBA and this alone will elevate your stereo like you won't believe.
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chilli42,
You may find this link helpful for screens. I use a 100”, tab tensioned model that rises from behind and at the level of my front cabinet. When down, it can’t be seen. 15 minutes to mount the 2 wall brackets and use with an ultra short throw projector and it’s an easy set up to HT. https://vividstormscreen.com/I use full range Voxativ widebanders  the 2 channel and matching doesn’t exist. As already mentioned above, Klipsch sounds close as they use horns and are closer than most brands to matching the efficiency of the Unos and the Vox. Have fun.