During box construction, temporarily assemble the box to make sure all pieces line up
properly. Then assemble all pieces before cutting out the holes for the woofers. Once the
box is fully assembled, connect an oscillator/amplifier to the
sweep it through 20-
100 Hz, and listen for strange air whistling noises, buzzes, and rattles. Since the box will
eventually be mounted in a car it should be firmly fastened down. Simple
shaped
brackets work well.
BASIC MATH CALCULATIONS
To build a subwoofer box some very basic math calculations must be made accurately
referencing the formulas and drawings below:
VOLUME AND AREA CALCULATIONS
AREA:
VOLUME:
Circle (port opening)
A = 0.79 x d x d
N / A
Rectangle
A = h x w
N / A
Triangle
N / A
Cylinder (Port tube)
N / A
Rectangular box
N / A
V = h x w x d
Triangular box
N / A
Cone
V = 0.26 x d x d x h
AREAS
.
d
Speaker parameters and box calculations often need some kind of math conversions in
order to make the numbers easy to work with. Some common conversions are listed
VOLUME AND AREA CONVERSIONS
TO CONVERT FROM:
MULTIPLY BY:
TO GET:
Inches
I O . 0 2 5 4
Meters
Square inches
0 . 0 0 7
Square feet
1 4 4
Cubic inches
0 . 0 0 0 5 8
Cubic feet
1 7 2 8
Liters
0 . 0 3 5
Meters
Inches
Square feet
Square inches
Cubic feet
Cubic inches
Cubic feet
Summary of Contents for PC105
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