I auditioned 2.4's, and subsequently picked up a pair of 3.6's used (I had auditioned them new, but many years before). FWIW, the 3.7 has been rumored to be "right around the corner" for some time, but in my correspondence with Thiel, they intimated that they would not offer a new model unless and until they felt that they had a significant improvement to offer over and above the existing model. The implication was that they still haven't come up with a speaker that fits the 3.6 mold, but offers a significant improvement. They also indicated that the 3.6 has had one of the longest production runs without being replaced by another model. To me, this means two things. Yes, it is older technology, but it also means that they got a number of things right when they designed the 3.6.
The first thing that hits you is that the 2.4's (36Hz to 25kHz +/-2 dB) have no where near the low end extension of the 3.6's (29Hz to 20kHz, +/- 1.5 db). Personally, I would not consider the 2.4's without a quality subwoofer (unless you have a very bass-enhancing room), while the 3.6's in the right room with the right amp(s) can get by quite well without a subwoofer. Others will be more than happy, though, with the low end output of the 2.4's, but I'm a bass player, so my tastes may be a bit different. Also of note, the 2.4's are more efficient (87, versus 86 db). I felt that the 2.4's had better midrange focus and were more airy on the high end, but they were not as convincing on the dynamics, and did not carry the same weight and authority of the 3.6's. The 3.6's, by contrast, did sound a bit veiled by comparison, but I found that I enjoyed their more full sound, and to me, they were a bit more musical and involving, while the 2.4's were precise almost to a fault.
As noted, though, the 2.4's are likely to sound "faster" and are probably a closer match to your Odysseys than the 3.6's. Their upper-mid and high end detail really is amazing, and the imaging is excellent. Still, when I listen to large orchestral pieces, or loudish rock music, I like to sound like I am "there", and to the 3.6's convey a more "real world" experience, while the 2.4's are like a surgical analysis of the real world, if that makes any sense. Please also note that the 3.6's are notoriously difficult to drive. I have heard that the 331 is borderline when it comes to driving the 3.6's, but the Dreadnaught II in 2-channel mode probably has the juice. In fact, the Dread II is one of the amps that I am considering as an upgrade for my 3.6's.
Hope this helps, Tom.
The first thing that hits you is that the 2.4's (36Hz to 25kHz +/-2 dB) have no where near the low end extension of the 3.6's (29Hz to 20kHz, +/- 1.5 db). Personally, I would not consider the 2.4's without a quality subwoofer (unless you have a very bass-enhancing room), while the 3.6's in the right room with the right amp(s) can get by quite well without a subwoofer. Others will be more than happy, though, with the low end output of the 2.4's, but I'm a bass player, so my tastes may be a bit different. Also of note, the 2.4's are more efficient (87, versus 86 db). I felt that the 2.4's had better midrange focus and were more airy on the high end, but they were not as convincing on the dynamics, and did not carry the same weight and authority of the 3.6's. The 3.6's, by contrast, did sound a bit veiled by comparison, but I found that I enjoyed their more full sound, and to me, they were a bit more musical and involving, while the 2.4's were precise almost to a fault.
As noted, though, the 2.4's are likely to sound "faster" and are probably a closer match to your Odysseys than the 3.6's. Their upper-mid and high end detail really is amazing, and the imaging is excellent. Still, when I listen to large orchestral pieces, or loudish rock music, I like to sound like I am "there", and to the 3.6's convey a more "real world" experience, while the 2.4's are like a surgical analysis of the real world, if that makes any sense. Please also note that the 3.6's are notoriously difficult to drive. I have heard that the 331 is borderline when it comes to driving the 3.6's, but the Dreadnaught II in 2-channel mode probably has the juice. In fact, the Dread II is one of the amps that I am considering as an upgrade for my 3.6's.
Hope this helps, Tom.