is 7db more speaker sensitivity a great big upgrade?
option 1: should i stick with my Infinity BETA 50's with dual 8 woofers with 91db/1 watt sensitivity
or
option 2: get the new JTR Speakers Triple 8 with 98db/1 watt sensitivity
Mike, is this a rhetorical or test question? 'You are like, an AH granddaddy' (said in valley girl accent) and have probably forgotten more than what most know... Maybe this is one of those instances

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How far are you sitting from the speakers? Ignoring all else, the higher sensitivity will matter only if you are sitting very far away, by way of, requiring less power to drive to same SPL at the seat. So your amps will run cooler.
With respect to the comment on headroom, i guess, if there is sufficient headroom for the Infinity Betas, it will probably not make a noticeable difference if you have more headroom on the JTRs.
If there will be any difference in sound quality? Well the Beta 40's are very capable and if you have treated and eq'ed to optimize the room response, I cannot see anything to justify the expense.
If it matters, the JTRs are fugggggllllyyyyy by comparison. I know, I know, we know better than to buy speakers for their looks, but let’s be realistic. It is a HOME THEATER, so there is something to be said for looks and aesthetics. Alternately, if you have a dedicated HT that looks something like a pro theater, well...