I was originally going to go sealed 2.1 cuft enclosure for a pair of Soundsplinter RL-p 15"s from my box builder. However, he worked out the specs and told me a 4th order bandpass would work better and worked out a response curve. What do you think? Will this work better for Sound quality purposes? The yellow line is the response for sealed 2.1 cuft and the teal is bandpass response.

He didn't give me any enclosure size details except the exterior dimensions... " The dimensions you will want to know about are 31"d, 41"w, 18"h at the front, 4" high at the back, and the horizontal part of the box extends 10.75" from the front, which is the depth needed for the sealed chambers to work out to their appropriate volumes, plus the width of the front panel and baffle. For the purposes of voice coil heat dissipation, I would recommend putting the motors in the vented side of the enclosure. "

Opinions?

4th order bandpass at best it only going to be as loud as sealed, band pass boxes are good when you want to do a very specific frequency range, otherwise, you'll need 6th order or higher to match the sensitivity of a ported box (if you even can). In this case, the RL-p is a very dampened driver so it will naturally roll off in a sealed box faster than a higher Q driver, but like any driver, this is corrected with moddest EQ. The sealed system should be louder once you add EQ to it. The driver will take it just fine, it really comes down to amplification.

Also, what is hard to understand in that graph is that the bandpass box is going to roll off with no saving grace (about 18-20dB per octave) after resonance, but the sealed box rolls off slower and like I said, it can be EQ'ed, where as the bandpass box will be unloading below resonance and doomed for the low frequencies, at least where it seems to be tuned at the systme you have now. An impedance graph would lend more information.

forgot to say, if you're going to for for 4th order bandpass, you might as well just port it. Which is basically your bandpass response + sealed response and in that case you can tune it lower and cover more frequencies with better efficiency.

The main advantage I see with a 4th order bandpass is the capability to have the driver in the trunk ported into the cabin.

Eh, I'd just go sealed.

Thanks guys, I think I will go sealed and EQ a bit. Should save me some cash too. The smoother/slower dropoff should work better for SQ purposes and I was planning to build a separate ported enclosure myself for future competition.