This will be exclusively HT use. I only use the back 24s for music. I'll differ to your judgement on this. These will be crossed with my 24s, probably in the 50-60Hz range. As for cabinet complexity, I'm not worried about it. I'm sure I can figure a way to build whatever you come up with.If I punch the height it will have lower peak/dome in the response, it would be more close to 70Hz. I can blow up velocity some and lower the tune to say in the form factor. Efficiency really picks up once you are a little above the Fs of the sub, in this case 30Hz. The extension would be worth it if you plan on running just the MBMs for music purposes. If you area always running the 24"s you will probably be crossing over between subs somewhere between 40Hz and 50Hz.