Why does it matter if my speakers are 4 OHMS or 8 OHMS
The job of an amplifier is to move a speaker cone outwards. This movement shifts the air in front of the speaker cone, which in turn creates sound. Since the speaker cone doesn't particularly want to be moved, it offers a resistance to the amplifiers' efforts. This resistance is called IMPEDANCE.
It is very important to know the impedance specifications of your amplifiers and speakers. They should be printed on the chassis, and/or in the users' manual. When the power output of an amplifier is specified (100 watts, 500 watts etc.), it is telling you that the amplifier is designed to deliver that amount of power when fighting against a specific impedance.
If the impedance is increased, the amplifier delivers less power than it is capable of, and if the impedance is reduced, the amplifier tries to deliver more power than it is capable of. Neither of these situations is ideal and in the latter case the amplifier will either cut out due to built-in protection circuitry, or damage may occur. You should never run an amplifier below its' minimum recommended impedance.
There is a formula to calculate speaker impedances when connected in parallel and another for connecting in series. Since however we usually work with multiples of two enclosures and nearly always connect in parallel, the rule of thumb is that if you connect two enclosures of equal impedance together, the impedance is cut in half.
So connecting two 8 OHM speakers gives an impedance of 4 OHMS.
connecting two 16 OHM speakers gives an impedance of 8 OHMS.
connecting two 4 OHM speakers gives an impedance of 2 OHMS. Remember ! A stereo power amplifier should be treated like two separate amplifiers in one box. You have to apply the above rules to each side individually.
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The job of an amplifier is to move a speaker cone outwards. This movement shifts the air in front of the speaker cone, which in turn creates sound. Since the speaker cone doesn't particularly want to be moved, it offers a resistance to the amplifiers' efforts. This resistance is called IMPEDANCE.
It is very important to know the impedance specifications of your amplifiers and speakers. They should be printed on the chassis, and/or in the users' manual. When the power output of an amplifier is specified (100 watts, 500 watts etc.), it is telling you that the amplifier is designed to deliver that amount of power when fighting against a specific impedance.
If the impedance is increased, the amplifier delivers less power than it is capable of, and if the impedance is reduced, the amplifier tries to deliver more power than it is capable of. Neither of these situations is ideal and in the latter case the amplifier will either cut out due to built-in protection circuitry, or damage may occur. You should never run an amplifier below its' minimum recommended impedance.
There is a formula to calculate speaker impedances when connected in parallel and another for connecting in series. Since however we usually work with multiples of two enclosures and nearly always connect in parallel, the rule of thumb is that if you connect two enclosures of equal impedance together, the impedance is cut in half.
So connecting two 8 OHM speakers gives an impedance of 4 OHMS.
connecting two 16 OHM speakers gives an impedance of 8 OHMS.
connecting two 4 OHM speakers gives an impedance of 2 OHMS. Remember ! A stereo power amplifier should be treated like two separate amplifiers in one box. You have to apply the above rules to each side individually.
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