If I go from a sealed to ported? ported to bandpass? I know a ported enclosure generally yields more spl, and bandpass tends to be boomy. But on average...how much of an increase if I go from sealed to those boxes?

 

Depends on the specs of the sub as to whether you get a gain or not. Some subs are designed to work better in sealed enlosures. Same principle goes for ported/bandpass. Tube ports use length and diameter to tune to a specific frequency whereras a bandpass plays a range of frequencies. Check the specs on the sub and see what the company reccomends. I know from my past dealings with fosgate that their subs perform better in ported enclosures.(but that has been a while.) I got about a 5db gain by going from tube ports to slot ports(like a vtech box) with 2 power hx2 12's.

 

I think I read somewhere that when you go to ported frmo sealed its about a 3 db increase. Not entirely positive though.

 

not sure of the exact db gain but I dont think i'd recomend a bandpass box for anything, specially not RF speakers, i had 3 hx2's in a sealed box and now im switching to 2 in a box with slot ports, should just be an all around better set up specially with my bigger amp, I'll let ya know how it works out
also remember with round ports or slots your going to get much deeper bass but loose a little bit of SQ you'd have with a sealed box

--Dan