I just finished up this design for countrywv he sent in the 4550 and I had a TD12M from Brain6751 who sent that over for a in wall project that never came to light. So you can thank both of them for helping this design come about. The AE/BMS driver pair work well together the only hiccup that needed to be addressed with extra parts in the xover is the peak around 18k in the response of the 4550. Crossover is around 1350Hz. After much listening I settled on a response that gently tapers as it rises starting around 800hz-1k. This results in slightly laid back top end which I feel does better as the volume get cranked up. However the response can be adjusted back to flat easily with a quick value change of a capacitor. I really like the midrange of the TD12M and my distortion graphs show why, at 2.83v input (around 95dB) distortion between 550-1500K is at or below 0.1%!!! I found the bass response to be very good in the 1.6cuft enclosure I was using but you don't get too much below 50-60hz from it. On axis SPL and Phase at 2.83v: Distortion at 90dB & at 2.83v. You may notice the spike just below 400hz, I believe that is a surround resonance since after I saw the spike I played a sine wave through the speaker around 390hz and checked for things that could have been rubbing or buzzing at that frequency. I have had a loose screw on my stand do something like that before. Anyway after looking around for a while I accidently pressed my thumb against the surround and the sound noticeable changed. When I pressed the cone lightly it did not so I figured the surround must be resonating at that frequency. The dip just above could also be part of that but then again it could be diffraction or ground bounce issues or a combination of all three for that matter. However during normal playback I never noticed any issues and even with that spike it is still below 1% distortion. 0-60 degrees off axis horizontal, sorry forgot to take vertical: Crossover schematic, the 1.5uF cap in parallel with the 33 ohm resistor can be swapped for a larger one to flatten the response, 3uF will make it very close to flat. I suggest trying it with the 1.5uF to see how you like it then then adding other small ones in parallel with it say starting with a 0.5uF and if that is not enough a 1uF or both the 0.5 + 1 to make 3uF with the 1.5uF. I'll supply a PE parts list if you want but you should be able to figure out most of the parts I used for countrywv's from the crossover photo. Crossover's built for countrywv:
I'm thinking about going down this path with the BMS driver over the DNA-360, but is it worth the extra cost? From what I can gather it should allow a lower crossover point, however you have used 1350hz, so its benefit is kinda negated. Interested to hear some thoughts.
The BMS 4550 does have slightly lower distortion then the DNA-360 below 1.5k, but also has slightly more around and above 2k. However the TD12M has even lower distortion then either CD around the crossover. The crossover I ended up with was really just chosen where it aligned the phase of the two drivers best. Bill's TD12M/360 design sounds really similar with a slightly more laid back midrange and a bit more top end, of course the top end can be adjusted to flat on mine as well but I felt it sounded best with the slightly tapering response.