How do i figure out size for my box?
I have an Alpine SWR-1241D sub, and this winter break, I wanna do a nice trunk install. My question, how do i figure out what size box to make, and if I need ports? Here are the specs on it
Diaphragm Material : Kevlar Reinforced Pulp
Magnetic Weight : 89.4oz.
Mounting Depth (top mount) : 178mm (7”)
Mounting Diameter (top mount) : 275mm (10-7/8”)
Recommended Box Types : Sealed/Vented/Bandpass
Recommended Sealed Box Volume : 0.7 – 1.0 cu. ft.
Spider Material : Nomex
Voice Coil Diameter : 50mm
Coil Height (Hvc) : 37.74mm
Cone Area (Sd) : 467.59 sq. cm
D.C.Coil Resistance (Re) : 3.6 ohm + 3.6 ohm
Electrical Q (Qes) : 0.45
Equivalent Suspension Stiffness (Vas) : 58 liters(2.04cu.ft.)
Free Air Resonance (Fs) : 28Hz
Frequency Response : 24Hz - 1kHz
Gap Height (Hag) : 10mm
Impedance (Nominal) : 4 ohm + 4 ohm
Inductance (Le) : 3.85mH at 1kHz (1.34mH at 20kHz)
Linear Excursion (X linear) : 13.87mm
Maximum Excursion (X peak) : 27.7mm
Mechanical Excursion (Peak-to-Peak) : 55mm
Mechanical Q (Qms) : 8.31
Sensitivity : 87 dB/W/M
Total Loudspeaker Q (Qts) : 0.43
What I wanna do is have the sub, and 6 inches in front of it a plexi piece, which would be 14in by 14in, and all around vinyl wrapped mdf for the back of the trunk. If someone could help me get the sizes together that would be nice..it's coo because my dad wants to help me out on this! He's good w/ wood working!!
Thanks in Advance
Diaphragm Material : Kevlar Reinforced Pulp
Magnetic Weight : 89.4oz.
Mounting Depth (top mount) : 178mm (7”)
Mounting Diameter (top mount) : 275mm (10-7/8”)
Recommended Box Types : Sealed/Vented/Bandpass
Recommended Sealed Box Volume : 0.7 – 1.0 cu. ft.
Spider Material : Nomex
Voice Coil Diameter : 50mm
Coil Height (Hvc) : 37.74mm
Cone Area (Sd) : 467.59 sq. cm
D.C.Coil Resistance (Re) : 3.6 ohm + 3.6 ohm
Electrical Q (Qes) : 0.45
Equivalent Suspension Stiffness (Vas) : 58 liters(2.04cu.ft.)
Free Air Resonance (Fs) : 28Hz
Frequency Response : 24Hz - 1kHz
Gap Height (Hag) : 10mm
Impedance (Nominal) : 4 ohm + 4 ohm
Inductance (Le) : 3.85mH at 1kHz (1.34mH at 20kHz)
Linear Excursion (X linear) : 13.87mm
Maximum Excursion (X peak) : 27.7mm
Mechanical Excursion (Peak-to-Peak) : 55mm
Mechanical Q (Qms) : 8.31
Sensitivity : 87 dB/W/M
Total Loudspeaker Q (Qts) : 0.43
What I wanna do is have the sub, and 6 inches in front of it a plexi piece, which would be 14in by 14in, and all around vinyl wrapped mdf for the back of the trunk. If someone could help me get the sizes together that would be nice..it's coo because my dad wants to help me out on this! He's good w/ wood working!!
Thanks in Advance
You decide ports by the sound you want. Ports are harder to build cause they are more sensitive to differences in volume. I think sealed tends to sound better but if you deisgn the ported right it could sound good. Ported tends to be louder. Do a google search for box size calculator and many will just let you punch in the specs and give you the optimum box size.


