Box for alpines

[quincyj34]

Im designing a box for a alpine type r 15 and the specs that Alpine recommend seem too small. It looks like for a port box they recommend 2.9cu. gross at 29hz! Should I just roll with that or go bigger? This will be on 1000w.

[Triticum Agricolam]

So gross volume doesn't matter, what we care about is net volume. Alpine recommends 1.5 - 3.0 cubes, which definitely on the small side as far as 15"s go, but every sub is different and these do well in small boxes. There really is no "right" number for internal volume, it depends on how you like your subs to sound. The larger you make the box, the more peaky and boomy it gets around tuning (they recommend 30 Hz BTW). The smaller the box the more even the sound is, but you give up some max performance.

Their "optimal" box has 2.25 cubes of net airspace, which is probably how I would build it, but I like more even sounding bass. If you want more low end output build it a little bigger.

I would not use their recommendation for port size though, for some reason Alpine always way undersizes their ports. I would use at least 30 - 35 sq in of port area for a 2.25 cube box and 35 - 40 sq in for a 3 cube box.