Have 1996 vintage mirage OM-6 speakers wondering if 180 center is a good marriage for om6?

It uses a titanium tweeter like the 180 so it's a close match. Even if the two tweeters weren't the same, my experience says it would be ok. I've owned and heard many systems with centers that are a different brand than the mains and all was fine.

Welcome, harve. The best help I can give you would be to contact Andrew Welker at Axiom via PM or better yet, give Axiom a call and ask for him. He was instrumental in the developement of the beautiful OMD speakers when he worked for Mirage/Energy under API. He may be able to give you the best advice....

Per Axiom's Design Team page...

Andrew Welker - After graduating with a degree in Electrical Engineering Andrew went on to join the R&D team at API (Audio Products International) makers of Energy and Mirage product lines. He was working directly for API's head of engineering Ian Paisley, who was also a member of that handful of loudspeaker designers who participated in the NRC research project, and to quote Ian Colquhoun "one of the finest loudspeaker designers to ever grace this planet".

Andrew spent over 10 years at API and ended up being the head designer for all the Mirage products. Andrew is a brilliant loudspeaker designer who has a broad knowledge of everything audio and a particular expertise in the science relating to the omni-directional psychoacoustical effects of loudspeaker reproduction. Andrew joined Axiom in 2009.

Please leave Andrew alone. He's working on the stuff I'm gonna buy next.

TY, have placed call to andrew.