I'm disappointed in myself for not doing the calculations to figure out, before I purchased and used them, that the QPOWER HD 12 four hole boxes are smaller than advertised. I just assumed 1.6 cubic feet of "airspace" meant the interior measurement. My incorrect assumption about the size is why I picked them. In any event, I've been kicking around in my head some ideas to add more cubic feet.
First, I thought about building up the front of the box. However, I'd have to add four inches to the front to get each enclosure up to 1.6 cubic feet. That seems like more trouble than just starting over and building new boxes from scratch.
Second, in theory, I could modify these four box enclosures into two box enclosures. I could cut out two of the braces on the inside, creating two enclosures that are twice as large instead of four small ones. Then I could attach a new face board over the top of the existing front of the cabinet to seal off two of the round holes. That would give me 2.6 cubic feet per box, which may be too much (is it?), but I could add some of my scrap 2x4s as extra bracing to shrink it down to 2.0 or less. In addition to the work making modifications, another downside is that I'd be kicking half of my subs out of their new homes, so I'd have to buy more cabinets and modify them too.
We promptly went on vacation when I finished the project, so I really don't know how well they're going to work "as is." I'll play around with them for a while before deciding whether to change anything. Still, it's annoying me that I bought smaller sub boxes than I had intended.
Last edited by Blue; 06-11-2019 at 09:55 PM.