JBL Everest DD67000 vs. Avantgarde Duo Mezzo

I am not sure about Avantgarde Duo Mezzo’s sensitivity comparison with JBL DD67000.

Avantgardes are semi-active loudspeakers. In case of Avantgarde Duo Mezzo (107 dB), there is a 500 watts Class AB amplifier for 12" woofers; external amplifier is only powering horns till 170 Hz. Whereas, JBL DD67000 (96 dB) is a pure passive loudspeaker. I suspect it’s sensitivity will also go really high if there was a built-in 500 watts amplifier for 15" woofers. And some people are doing active bi-amping with low power amplifier for the bi-radial horns and massive amplifier for woofers.

Right. As I mentioned, the issue of sensitivity bears on the kind of amplifier that can be used, and the SET is magic with the horns. However, at least with the older Duo, the issue is continuity or blending of woofers to mid horn. And the powered woofers are fed at hi-level inputs through jumpers from the output of the SET amp, so the self powered woofers are supposed to retain the character of the main amp. They may, but at least on the older Duo, you still have the horn v. dynamic speaker discontinuity in character I spoke of upthread. It can be ameliorated to a large degree, but it’s there. I’d have the same question if you bi-amp the JBL with different amps, but would be interested to know how that sounds.
PS: what external X-over has been recommended? The one thing I do like very much about the Duo (and assume it is true on the Mezzo) is the absence of any x-over on the mid-horn. I think it contributes to the speakers "un-reproduced" sound.  

The Avantgarde Duo Mezzo's are a work of art, they also have a broader frequency response than the JBL’s.
That said, with the wrong amp the ADM’s can have an in your face sound.
On the other hand I have found JBL’s to be .... well - sound like JBL’s.

I realize it’s a horse of a different colour, but if you’re going to spend that kind of money, at least give the MurAudio PX1s an audition. I have yet to hear a speaker that sounds as life like, transparent, and dynamic as the PX1’s, not to mension their broad frequency response. In other words "real". You can also save yourself $10 grand with the MurAudio’s over the JBL’s.

Having is having owned Duo Omegas since the last 10+ years. And having heard the Duo Mezzo's often, the Everests 67000 are ahead of them. Just heard the JBL's on the weekend gone. 
The drivers have less distortions in the JBL, than the Mezzo's. 
Chise your amplification carefully with the Mezzo, as they are very unforgiving. But you get that right and you can be in sheer heaven. 
Similarly the JBL's will need more power and depending on your preference an OTL or solid state low distortion amp will get you there. 

Good luck. 

Regarding the Duo Mezzo's, would they be too much speaker for a 13x12x8 room? Would Shindo D'Yquems (18wpc) be a good match for them? Do they play all styles of music well, i.e., Americana rock, Afro-Cuban, Classical, acoustic Jazz? Thank you!