Mike Lights, Inc. 
 

Speakers and Impedance

 
Impedance and loudspeakers The impedance of the loudspeaker varies from 2 - 30 ohms. 
Amplifiers must be used that can cope with the impedance of the speaker. If the speaker has 
an impedance lower than the amplifier, the sound may be distorted and the amplifier damaged. 
If the speaker has a higher impedance than the amplifier, the sound level will be low.
 
Serial speaker connection  Paraller speaker connection
Speakers wired in series. Speakers and drivers are wired in series to match impedance to the type of amplifier being used. To find the total resistance in series circuit, simply add together all resistors. Formula to define resistance in a series circuit is:  Speakers wired in parallel. Speakers and drivers are wired in parallel to match impedance to the type of amplifier being used. Resistors in parallel circuit are a little more difficult. The formula for two resistors in parallel is:
Total resistance = R1+ R2  Total resistance = (R1 x R2) / (R1 + R2)