The Electro Voice ZXa Series is a great line of speakers and sounds excellent
But unfortunately, the only choices you have so far are the ZXA1 and ZXA5. I own some ZXA1s, and although they sound great, I couldn't honestly say that they play loud, at least not compared to the other contenders mentioned. The ZXA5s, which I haven't heard but are reputed to be very good, are considerably more expensive than $500/box.
What E-V needs is a ZXA3, but so far that doesn't exist (and it won't be anywhere near $500 either).
The LiveX line looks interesting, although they are using smaller HF drivers that the ZX3 and 5, which concerns me a bit.
GTD
