 # Speaker Formulas and Calculations

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