I know that ported boxes are more for SPL and sealed are more for SQ. What about bandpass? Are they better for SQ or SPL, or just in between? Thanks for help!
Strictly SPL because they sound like crap. Worst sounding box out of all of them. They aren't full range, they are tuned to a certain center frequency, usually tuned to the resonant frequency of the car.
you can have excellent SQ with a ported box, tune it in the high-mid 20's and the sub will have to drop lower for when the port noise comes into effect, thus giving greater SQ than if tuned at 30-40-50 Hz
also, bandpass boxes are extremely complicated to design, but can be worth it in an SPL comp giving up to +24 dB gains at certain frequency spikes - not good for daily deliver setup