I built several of these cabs over the years for myself and friends on a low budget. Some were slapped together really quick out of cheap 3/4 ply with a skilsaw and a little sloppy, but nothing a belt sander and a little bondo couldn't remedy. The last two I built in a professional carpenter shop back in 1988. I've been using them since for things from pa, guitar, bass, and an old stereo. For years they were loaded with a Peavey Scorpion 15 and an EVM15L. In comparasin, I really liked the Peavey speaker's sound better for bass. Before I built these, I built a double cab with the 15 side to specs, and added enough cab width for a 12 Celestion greenback. I used no insulation for the 12. The two speakers were independent of each other. Huge cab, with a huge, deep sound through my small box plexi with a Strat. This was "MY" guitar sound I liked since I was 18, and I still like the combination of a 15 and 12. I still will use the 15" cabs playing in stereo with a pair of Marshal 4010 combo 112's for guitar when not using a 412 and head.
Last year I pulled the Peavey and EV speakers and added Kappalite's.
Been using the Kappalites for about a year now, but just yesterday I compared them to a Bergantino AE410.
The Berg won me over big time and I bought it.