Hmm. Did you ever install WinISD
@MrBoat? Figuring you'd build your 11 x 15 x 17 box out of 0.75" MDF with bracing and basket displacement offset by polyfil, that's a ~1.15 cubic ft box. That sub would have a Q of 0.881 in such a box, which is pretty high. Target Q for a critically damp sub is 0.5. Also, the sub is -3dB at 47 Hz in such a box. That tuning might be pretty close to correct in a car once you add cabin gain, but I don't think this is a good driver for a sealed sub in a house.
Vented in that size box is better, but still ~5dB down at 40 Hz. You could do a 3" vent at 7 9/16" and not have to deal with any bends while supplying the sort of power that won't bottom out your sub (about 30 watts, for 100 dB @ 40 Hz, 105 dB @ 65 Hz, bottoming out at around 30 Hz, and port chuff just shy of 16 meters / second).
Believe it or not, a 4th order bandpass with this driver is pretty interesting. It won't play loud, only around 92.5 dB from 50 - 100 Hz at 40W. But trading overall SPL you gain deeper extension. There's a 4dB rise going from 50 down to around 32 Hz, and this config will have an F3 of around 23 Hz (or maybe a bit lower with Polyfil in the rear chamber). This is figured with a rear chamber sealed at 0.6 cubic feet, the front chamber at 0.4 cubic feet, and the front chamber vent tuned to 42 Hz (2.5" vent, 16 7/8" long).
Both the vented and the bandpass configurations center the impedance dip and place the minimum cone excursion right at the driver's Fs (assuming Madisound's spec sheet can be trusted).
Blue = sealed @55W; Green = vented @30W; Red = bandpass @40W
SPL:
Cone excursion:
Impedance:
WinISD figures vent lengths with one end flared. If you plan to flare both ends, you'll need to lengthen the vents accordingly.