I recently acquired a pair of Infinity Qa speakers, and used the information in this thread to help me repair the one tweeter that was not working: http://audiokarma.org/forums/index.php?threads/emit-emim-tweeter-diaphragm-repair-how-to.65571/ (Reading a later post about the magnets was really useful. Thanks to all who added useful information in that thread.) Anyway, they sound really great for old speakers that were "bottom of the line" when they came out (though almost $300 for a pair back then was plenty of money, too much for me at the time). And the woofers seem to integrate well with the tweeters. I am not the only one to think so; you can read a Stereo Review article about them at: https://bobbyshred.baberuthband.co.uk/infinity/qa.html in which they say, among other nice things: The high-end response, in particular, was at least the equal of anything else we have heard in regard to smoothness and dispersion. Furthermore, it was so well blended with the woofer output that we felt a sense of listening to a single unified sound source. Now, since the Infinity Qb uses the same woofer and tweeter, and simply adds a midrange unit (which I would normally expect to be a good thing with a 10" woofer), how much better can it be, if at all, given how well the woofer already integrates with the tweeter in the Qa? This is a purely academic question for me, since I am not planning on buying the Qb (but who knows? I was not planning on buying the Qa). Do any of you have both models of speakers presently, and, if so, what are your impressions of the differences between these speakers? What good is a midrange driver added to a system in which the woofer and tweeter already integrate so well? Or, if not having them presently, do any of you remember listening to both models in the past, and, if so, what were your impressions of the differences? I know, this is a subjective sort of question, and I welcome all perspectives on it.