QP124D - 12” Subwoofer
Installation Instructions / Owner's Manual
QUANTUM AUDIO
Tel: 956-428-4263 Fax: 956-421-4513
PRODUCT SPECIFICATIONS
Free Air Resonance.
(FS)
33
.54
Total Q of driver @ FS including all resistances.
(Qts)
(Qms)
(Qes)
Q of driver @ FS including non electrical resistance only.
Q of driver @ FS including electrical resistance only.
7.98
.49
The driver's compliance expressed as an equivalent volume
of air (Cubic Ft.).
(Vas)
(Xmax)
(Re)
2.9
.31
6.4
The driver's linear displacement (inches).
The DC resistance of the driver's voice coil (Ohms).
Thermal power rating of driver (R.M.S./Peak).
The driver's voice coil inductance (millihenries).
The driver’s sensitivity (dB).
(Pe) 400 / 800
(Le)
4.03
89
(Sens)
CALCULATING ENCLOSURES
It is difficult to give exact box dimensions that are universal for all cars and trucks. It
is for this reason that you must be able to calculate the space in which you have
available in order to achieve the proper air volume required.
It is recommended to build your enclosure from 3/4" thick MDF (medium density
fiberboard). Make sure the enclosure is sealed airtight.
Calculating External Volume
1.) To calculate box volume, measure the outside Width x Height x Depth of the
enclosure. Example12"x14"x9"=1512".
2.) Nextyoumustconvertcubicinchesintocubicfeet. Todothis, youmust
dividethecubicinchtotalby1728". Example1512÷1728=.875Cubicfeet
CalculatingInternalVolume
1.) To calculate the internal (net) volume of the above box you must first multiply
the thickness of the wood you are using by Two (2).Example 3/4" x 2 = 1.5".
2.) Nextsubtract1.5fromeachoftheoutsidemeasurementsofthebox.
Width
12-1.5=10.5
Height
14-1.5= 12.5
Depth
9-1.5= 7.5
3.) Multiplythenewtotals(HxWxD)Example:10.5x12.5x7.5=984.375
4.) Nextyoumustconvertcubicinchesintocubicfeet. Todothis, youmust
dividethecubicinchtotalby1728"Example984.375÷1728=.5696
cubicfeet.
QP124D
RECOMMENDED ENCLOSURES
PleaseNote:Oursuggestedboxvolumesaregivenasinternalairrequirements
Sealed Enclosure
Box Volume
*1.0 Cu Ft.
* Box is given as internal air volume including driver
displacement.
QP124D AAmplitudee Responssee (dB/Hz)
Sealed Ennclosure
12
6
F3 = 57
0
dB
-6
-12
-18
-24
5 Hz
10
50
100
500
1000
Frequuency
Ported Enclosure
Box Volume
*2.0 Cu Ft.
40 Hz
4 Inches
8 Inches
Port Frequency (Fb)
Port Diameter
Port Length
QP124D AAmplitudee Responssee (dB/Hz)
Ported Ennclosure
12
6
0
F3 = 38
dB
-6
-12
-18
-24
5 Hz
10
50
100
500
1000
Frequuency
QP124D REV 7.28.05
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