Originally Posted by Kevin A
I really enjoyed watching this build! Congrats on achieving your goals & winding up with some very nice subs at a reasonable investment!
Question for you (& others):
I currently have a single THT (24" wide) and am contemplating building a second THT. What would I gain (or lose) if I decide, in lieu of building the 2nd THT, to build two of these MFW-15 Dual Opposed subs (4 drivers) of approximately the same size in this thread ( 23.5x23.5x26.5; 22x22x23.5 internal)? These two would replace my single THT. I assume they'd dig down a bit further than my single THT (or possibly two), but how about output?
Single THT in my room:
IMO, you can't separate the room from the subwoofer. What are you room dims and does it have big openings?
I helped a friend build two THTs for his living room. We calculated the room volume at close to 9000 cu ft. It also had large openings to the rest of the house. He basically had no room gain. That fact combined with a restricted budget were the reasons why I suggested the THTs. They sound great, but his response looks like yours, nothing below 20hz.
Four sealed MFW-15s would have probably given adequate output to 20hz, maybe 15hz but they weren't available at this price. It also would have required a bigger amp, adding cost. With the current clearance on them, I'd consider 4 of them instead of the THT for his room, but I'm not certain it would be a better route.
In a small room, I'd go with 4 MFW-15's sealed in a heartbeat over the THT. I don't really see the point of the THT in smaller rooms. IMO, if your room shows nice room gain, you'd be better off using 2 of the THT drivers but in a sealed alignment than those same drivers in THTs.
If you want to know what kind of room gain you are getting, put a driver in a sealed box that you know the dimensions. Model it and then measure a sweep of it. Compare the curves and you will see what gain you have to work with.