I am doing a box for JL Audio12w7-3 driver. I prefer sealed box but I thought of making a ported box and seal the port for a sealed box effect. This driver is flexible enough for that as well as do a quarter wave tube. Here are the details. Any help would be appreciated.
Regards,
Jay Bala
JL audio suggests for a sealed box as below (car audio):
Qtc = 0.79
Vb (net) = 39L, 1.375 cu.ft
Fc = 44.7 Hz
F3 = 40.4 Hz
I like a Qtc=0.5 but the box size comes out to be near 30 cu.ft. Thats kinda big.
Qtc=0.79 gives 1.4 cu.ft
Qtc=0.67 gives 2.5 cu.ft
Qtc=0.64 gives 3.0 cu.ft
Qtc=0.57 gives 5.8 cu.ft
Qtc=0.50 gives 29 cu.ft
———
JL audio suggests for a ported box as below (car audio):
(This doesn't look to be for a SBB4 alignment.)
Vb (net) = 50L, 1.75 cu.ft
Fb = 36.7 Hz
F3 = 31.5 Hz
Slot height: 1.75 in
Slot width: 14 in
Slot length: 24 in
Slot volume from above: 0.34 cu.ft (much largewr than ported volume)
Total internal volume:
suggested net+drvier+slot = 1.75+0.14+0.34 = 2.25 cu.ft
Different box calculators on the internet gives different box volumes, one of them gives:
For SBB4 alignment,
Vb = 2.5 cu.ft
f3 = 25.5 Hz
fb = 27.2 Hz
Port diameter = 3 1/16"
Port length = 8.3"
TS:
Free Air Resonance (Fs) = 27.2 Hz
Electrical “Q” (Qes) = 0.514
Mechanical “Q” (Qms) = 7.807
Total Speaker “Q” (Qts) = 0.482
Equivalent Compliance (Vas) = 2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax) = 1.15 in / 29 mm
Reference Efficiency (no) = 0.25%
Efficiency (1 W / 1 m) = 86.2 dB SPL
Effective Piston Area (Sd) = 84 sq in / 0.0542 sq m
From Sd, driver diameter = 10.342 in, 26.27 cm
DC Resistance (Re) = 2.7 Ω (measured)
Driver Displacement = 0.14 cu ft / 4.0 L
Nominal imp = 3 ohms
minimum mounting depth = 10.5”
frequency response = 18-200 Hz
Amp power: 400W at 2 ohms
peak power handling = 2,000 watts
http://www.jlaudio.com/12w7-3-car-audio ... vers-92112