I am using 2 MTX Thunder 7000 10" subs powered by a Thunder 2300x and I would like to build a ported box that would kick butt. I enjoy good SQ but I also like to go to Db Drags. The last time I entered a show I hit 138.6 dbs, with them each in a 1 ft3 ported box with the port measuring 3x14.5 inches long and tuned to 37Hz. The note I played was 55Hz, but I found my highest note is 57Hz. Don't know if it makes much of a difference?.

I would really like to keep this box because it fits my daily driver very nicely.
Right now the box is rear firing with the slope side facing back.(Use to fire it toward the back seat).
Would it be better to seal the slope side and use the 90 degree side to mount the subs and ports so the the slope is at the back seat again?

What is a good subsonic filter? Already lost 2 7000's to track 8 on the DB Jams CD

Sorry for the long post. Just got excited you know a sound freak.

Many thanks in advance, should you choose to accept this mission.
These are the specs from the MTX website on these subs
T7108 Specifications

Free Air Resonance Fs 31.4 Hz
Volume Acoustic Suspension Vas 1.29 Ft^3 (36.6 l)
Total Q Qts .62
Electrical Q Qes .66
Mechanical Q Qms 11.92
DC Resistance Re 7.35 Ohm
Linear Excursion (One Way) Xmax .50” (12.7 mm)
Effective Piston Diameter D 8.250” (.2096 m)
RMS Power Handling RMS 400 Watts
Total Power Handling Total 1000 Watts
Sensitivity 1W/1m SPLo 84.5 dB
Reference Efficiency No 0.16%
Frequency Response 31 - 150Hz
Voice Coil Inductance Le 5.6 mH
Gap Height .375” (9.5 mm)
Voice Coil Height 1.250” (31.8 mm)
Motor Force BL 16.11 Tm
Compliance Cms .219 mm/N
Total Moving Mass Mms 117.6 g
Moving Mass of Driver Mmd 113.9 g
Suspension Losses Rms 1.94
Effective Surface Area Sd 53.5 in^2 (.0345m^2)
Mounting Diameter 9 1/4 ” (235.0 mm)
Overall Diameter 10 5/8 ” (269.9 mm)
Mounting Depth 4 7/8 ” (123.8 mm)
Overall Depth 5 9/16” (141.3 mm)
Speaker Displacement (Inside Box) 195in^2 (3.2 l)
Speaker Displacement (Outside Box) 134in^2 (2.2 l