I built a pair of Zaph BAMTM using the sealed option (Link below) with a bit more internal volume as my first speaker build. The extra volume also allowed them to be floor standing. The second speaker is a mirror image of the first. I am very happy with how they perform and like the look of the aluminum cones against the dark walnut. Thanks to the designer! Standard MDF box with solid oiled walnut fronts. I would give my construction/woodwork a B as I rushed it a bit but I did learn a few things on the way. My homemade circle template for my router needs some refinement and I just used some rattle cans for the paint on the MDF. Some drilled Lexan was used for the crossover boards but I probably should of just used some 1/4" ply or hardboard. I have a Technics SU-7300 (48 watt at 4 ohms) powering them. I have a Onkyo TX-4500 II (60W at 8 ohms) that I want to build speakers for next. Musically, I am fairly eclectic and likely to follow a Rush album with Willie Nelson. Any suggestions for my next project? I am kind of leaning towards larger version of these MTMs that would maybe use the Dayton DA215 (8") or even the DA270 (10").
http://zaphaudio.com/BAMTM.html
http://zaphaudio.com/BAMTM.html
I personally dislike the idea of big drivers MTM. Too many issues. Due to large midbass beaming, you have to use lower crossover frequency. This puts a lot of stress on tweeter, unless you plan to use small fullrange (like dave did).
Thanks for the input. The BAMTMs have a crossover at 1450HZ and I should of considered a larger speaker will be lower crossover. Just looking at the frequency response for the three speakers indicates a likely 250-300 Hz crossover drop for each successive size.
After Adason's input I see the reason why having larger drivers in an MTM creates problems selecting a tweeter due to the low crossover. I found some designs where a small full range was used and it may be the path to success if I want larger drivers. I'm not necessarily going to build another set of MTMs but I now have a starting point.
https://www.diyaudio.com/community/threads/planet-10-a7m-a12pw-ml-tl-build.359678/
You can use a dome midrange driver. For example, morel em-1308 or new Bliesma 3". I would now go this way.