2 Rel T7s or 1 Rel T9???

I'm replacing a pair of Rel T2s in my 2 channel system. Considering a pair of T7s or a single T9. Looking for opinions on running a larger single sub vs a smaller pair. My room is smallish, 12x19. For me, it's about the music not a floor shaking experience.
Thank you for your input and expertise. I am going with the pair of T7s! I think it makes good sense on several levels. Ben_wood, sorry to report, the T2s are gone on a trade.

Any suggestions for bass heavy recordings for sub run in period?

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Also - read the latest article about subwoofers in the Absolute Sound magazine, this month's. Everything I've read points to the superiority of two subs. Two 7's should be
You will be better off with 2 smaller subs which will diminish low frequency room modes. For detailled explanations, read Floyd E. Toole 'Sound Reproduction'.

no doubt that REL makes the best sub in the marketplace!
I would try (1) sub, 1st and after several months of dedicated listening, make a decision about adding the 2nd sub.

Keep me posted & Happy Listening!