Aside from a huge clearance on DCM TimePiece and TimeFrameEvolution (which appears to be completely dried up), the Infinity Reference and JBL Studio 5 series represent the best values at their prices that I have found!
I also have both and enjoy the differences. I would probably give JBL preference for HT and rock and Infinity the nod for Jazz and Classical, but they are both great at everything and I do love how "engaging" the JBL's are (perhaps the horns make them more dynamic? I'm not really sure!) but feel the Infinity are more refined. That is of course my totally subjective opinion!
The next better speaker I have found (at 600/pr) is the Canton Vento 826 (which is my preference) or the Elac DBR-62 (which is the "go to" if you like a less-forward, laid-back speaker). The Vento uses a ceramic tweeter like the Infinity (but the Vento is a superior execution - the Elac uses a soft dome)
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Bookshelf speakers
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The Canton Chrono SL 526.2 is also (as best as my ear can tell) audibly equivalent to the Vento. I believe the only difference is the really nice curved cabinet of the Vento. In the past, the Chrono was less expensive, but right now they are both $600/pr (historically, a
great price for the Vento and a "meh" price for the Chrono). I think the Chrono has been around $500 and maybe $450 for an open box return!
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So, yeah, it takes a bit more money to make a worthwhile step up, IMHO!