Sealed vs Ported (tested)
Lots of newer people on the scene ask the question of what is better, sealed or ported. The general response is "Sealed sounds better, but ported is a little bit louder and offers freedom to tune". I decided I'd find out how much a “little bit louder” is.
The Test System:
JBL W15GTi subwoofer
JBL A1201GTi 1200WRMS Monoblock
2x 900CCA batteries
0g wiring harness
Goldline DSP-30 RTA
Amp hooked up to CRO, gains adjusted @ 60 Hz until clipping, and then backed off. LP Xovers set to 80 Hz using CRO & DMM. DBO (subsonic + bass boost) set to 30 Hz, 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 @ 52 Hz
Ported, sub forward, port back, engine OFF: 152.6dB @ 52 Hz
Ported, sub back, port forward, engine ON: 154.0dB @ 54 Hz
Ported, sub back, port forward, engine OFF: 153.9dB @ 54 Hz
Sealed, engine ON: 135.8dB @ 52 Hz (1st peak)
Sealed, engine ON: 138dB @ 39 Hz (2nd peak)
Sealed, engine OFF: 135.7dB @ 52 Hz (1st peak)
Sealed, engine OFF: 137.9dB @ 39 Hz (2nd peak)