Speaker Formulas and Calculations


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The following chart contains commonly used conversions of length, area, and volume. Simply multiply what you want to convert by the number in the last column.

Length

inch to  millimeters X 25.4
inch to  centimeters X 2.54
inch to  meters X .0254
inch to  feet X .0833
millimeters to  centimeters X .100
millimeters to  feet X .00328
millimeters to  inch X .03937
millimeters to  meters X .00100
centimeters to  millimeters X 10.0
centimeters to  feet X .0328
centimeters to  inch X .3937
centimeters to  meters X .0100
feet to  centimeters X 30.48
feet to  inch X 12.0
feet to  meters X .3048
feet to  millimeters X 304.8
meters to  centimeters X 100
meters to  inch X 39.37
meters to  feet X 3.28
meters to  millimeters X 1000

 

Area

inch2 to  centimeters2 X 6.452
inch2 to  feet2 X .006944
inch2 to  millimeter2 X 645.2
inch2 to  meter2 X .0006452
centimeter2 to  inch2 X .1550
centimeter2 to  feet2 X .001076
centimeter2 to  millimeter2 X 100
centimeter2 to  meter2 X .0001
millimeter2 to  inch2 X .001550
millimeter2 to  centimeters2 X .0100
millimeter2 to  feet2 X .00001076
millimeter2 to  meter2 X .000001
meter2 to  inch2 X 1550
meter2 to  centimeters2 X 10000
meter2 to  feet2 X 10.76
meter2 to  millimeter2 X 1000000
feet2 to  millimeter2 X .000929
feet2 to  centimeter2 X 929.0
feet2 to  inch2 X 144.0
feet2 to  meter2 X .0929

 

Volume

inch3 to  feet3 X .0005787
inch3 to  centimeters3 X 16.39
inch3 to  meters3 X .00001639
inch3 to  liters X .01639
feet3 to  centimeters3 X 28320
feet3 to  inch3 X 1728
feet3 to  meters3 X .02832
feet3 to  liters X 28.32
centiimeters3 to  inch3 X .06102
centiimeters3 to  feet3 X .00003531
centiimeters3 to  meters3 X .000001
centiimeters3 to  liters X .001
liters to  centimeters3 X 1000
liters to  inch3 X 61.02
liters to  feet3 X .03531
liters to  meters3 X .001

 

Electronics

In many electrical circuits, the values of components are specified in units with prefixes. This makes the numbers easier to handle without long strings of zeros.

mega = X 106
kilo = X 103
milli = X 10-3
micro = X 10-6
nano = X 10-9
pico = X 10-12

E = Potential Difference (volts)
I = Current (amperes)
R = Resistance (ohms)
P = Power (watts)

Power (watts)
E X I
I2 X R
E2 / R

Potential Difference (volts)
I X R
SQRT( P X R )
P / I

Current (amperes)
E / R
P / E
SQRT ( P / R )

Resistance (ohms)
E / I
E2 / P
P / I2

Resistances in series
RT = R1 + R2 + R3 .... + Rn

Resistances in parallel
1/RT = 1/R1 + 1/R2 + 1/R3... + 1/Rn

Resistances in parallel (2 components)
RT = (R1 X R2) / (R1 + R2)

Capacitances in series
1/CT = 1/C1 + 1/C2 + 1/C3... + 1/Cn

Capacitances in parallel
CT = C1 + C2 + C3 .... + Cn

6dB High Pass
Series Cap = .159 / ( Impedance X Frequency )

6dB Low Pass
Series Inductor = Impedance / (6.28 X Frequency )

12dB Butterworth (high and low pass)
Capacitor = .1125 / ( Impedance X Frequency )
Inductor = ( .2251 X Impedance ) / Frequency

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