Lotsa newer people on the scene ask the question of whats better, sealed or ported. The general response is "Sealed sounds better, but ported is a little bit louder and offers freedom to tune". Decided I'd find out (after doing some response curve testing in a sealed enclosure) exactly how much louder ported is over sealed.


The Test System:

1x Ford Festiva Trio
1x JBL W15GTi subwoofer (DVC 6ohm, wired for 3ohm)
6.868 cube enclosure tuned to 52hz on ports.
3x Towels to plug ports for sealed testing
1x JBL Crown BPX2200.1 2500WRMS amplifier
2x SuperCharge Gold 900CCA batteries
1x Stock 60A alt.
1x 0g wiring harness
1x Alpine headunit (5V subout, unclipped)

Test Equipment:
1x DMM
1x Goldline DSP-30 RTA

Test Method:
Amp hooked up to CRO, gains adjusted @ 60hz until clipping, then backed off. LP Xovers set to 80hz using CRO & DMM. DBO (subsonic + bass boost) set to 30hz, zero boost, using CRO & DMM.
Enclosure strapped. Filler pack in wheel well and false floor installed.
For sealed tests, enclosure ports were plugged with towels. The enclosures response in 6.868 cubes sealed is as flat as it will be getting.
Engine idling @ 2,000RPM. Tests run with voltage on amp terminals showing @ 14.1V idle engine on, or 13.6V engine off.

Results show peak SPL @ freq.

Ported, sub forward, port back, engine ON: 152.7dB @ 52hz
Ported, sub foward, port back, engine OFF: 152.6dB @ 52hz
Ported, sub back, port forward, engine ON: 154.0dB @ 54hz
Ported, sub back, port forward, engine OFF: 153.9dB @ 54hz

Sealed, sub forward, engine ON: 135.8dB @ 52hz (1st peak)
Sealed, sub foward, engine ON: 138dB @ 39hz (2nd peak)
Sealed, sub forward, engine OFF: 135.7dB @ 52hz (1st peak)
Sealed, sub foward, engine OFF: 137.9dB @ 39hz (2nd peak)

Didnt test sub back sealed as it was getting dark, mozzies were eating me and the results would have been pretty much the same.

Make of this what you will. I merely do the tests and share the results.