Having had my share of woodwork in my hifi life (and there is some skilled work on this thread...way beyond my capability), I decided to take a different approach with my subs. I have been through many DIY OB designs, but in the end came back to boxes for the tops, and naked OB's for the bottoms.
Might not make much sense, but for me, boxes never worked for bass in my room, creating resonances, modes, cancellation, peaks & troughs. Eq helped to a certain degree, but was never quite right. A few years ago I stumbled on the naked clamshell design.....and have not looked back.
Some information on this thread:
https://www.diyaudio.com/community/...m-open-baffleless-full-range-speakers.374043/
There are a few caveats. This method of producing bass will never be efficient, but will go down low, sub 20hz in my case, if you choose the right drivers, for instance Dayton UM18's. These are directly coupled to my wooden floor, and produce rumble from 14Hz up to 60hz. Above that a pair of Focal Shape Twins take over. Integrating with a bookshelf speaker has always been a problem for me until I got rid of the reflex port and introduced a HPF. Now, the active Focals integrate perfectly with the UM18's driven by a pair of Behringer NX6000D's. A big test for integration is Electronic music where the artists will paint a picture with upper bass which only now has become clear to me. To enjoy this type of music I need a system that goes low, slams like a demon but retains control, and delivers tone, timbre & detail with no overhangs or boom, and without overpowering the higher frequencies.
This does it for me!
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