JBL GT-1081
THIELE-SMALL PARAMETERS
VOICE COIL DC RESISTANCE: REVC (OHMS) . . . . . . 7.56
VOICE COIL INDUCTANCE @ 1 KHZ: LEVC (MH) . . . . . . . 1.73
DRIVER RADIATING AREA: SD (IN2) . . . . . . . . 55.02
SD (CM2) . . . . . . 355.00
MOTOR FORCE FACTOR: BL . . . . . . . . 13.98
COMPLIANCE VOLUME: VAS (FT3) . . . . . . . . 3.17
VAS (LITERS) . . . . . 89.73
SUSPENSION COMPLIANCE: CMS (µM/N) . . . . 501.37
MOVING MASS, AIR LOAD: MMS (GRAMS). . . . . 60.61
MOVING MASS, DIAPHRAGM: MMD (GRAMS) . . . . 56.76
FREE-AIR RESONANCE: FS (HZ) . . . . . . . . 28.87
MECHANICAL Q: QMS . . . . . . . . . . . 6.55
ELECTRICAL Q: QES . . . . . . . . . . . . 0.43
TOTAL Q: QTS . . . . . . . . . . . . 0.40
MAGNETIC-GAP HEIGHT: HAG (IN) . . . . . . . . . 0.31
HAG (MM) . . . . . . . . 7.92
VOICE-COIL HEIGHT: HVC (IN) . . . . . . . . . 1.25
HVC (MM) . . . . . . . 31.75
MAXIMUM EXCURSION: XMAX (IN) . . . . . . . . 0.47
XMAX (MM) . . . . . . 11.91
The leak could very well be contributing to your problems by lowering the Q of the speaker to a level where it is actually counter productive. Seal it up right away....
JBL reccomends a .75ft^3 sealed enclosure for each subwoofer- so likely your enclosure is also contributing to the problem. Seal the enclosure first, and see what happens. If there is little change, a slightly larger enclosure may be needed.
The impedence of each sub being at 8 ohms could also be effecting this. Typically a speakers performance is hindered by more resistance.
Are your woofers phased correctly? Meaning- posative to posative and negative to negative on the wiring?
As you can see, this could be several things combined.
One other thing that you did not mention is your crossover frequency. It should be kept below 100Hz for a 10" model.
These are a few things that you can look into and see if they help.
take it easy,
-zane
