What Is a 6 Ohm Speaker?

Relationship to Amplifiers

Impedance dictates how much strain is placed on an amplifier. At six ohms most quality amplifiers are driven slightly harder than the more common eight ohm impedance. This typically produces more bass and slightly more volume than the higher impedance. Six ohm speakers are expected whenever a speaker has multiple bass drivers, or at least more than a single woofer and tweeter.

Normally, determining total impedance on one amplifier channel is not hard. For example, the impedance is based on taking a typical 10-volt amplifier output and dividing that by the amperage load provided by the speaker. For example, 10 volts divided by 1.67 amperes is roughly a six ohm load. This impedance is defined by the total electrical properties of the drivers plus the crossover network, dividing the frequencies.

You can create a six ohm load at the amplifier by combining two 12-ohm speakers in parallel at a single amplifier output. This kind of information is critical when designing loudspeakers, or combining individual speaker drivers in a car audio system. Most speakers follow this 2-to-1 ratio, additive if wired in series (two 6-ohm speakers in series equals 12 ohms), or deductive as above.

Always consult the information or specification sheet for the amplifier or receiver before connecting a 6-ohm speaker. Although the impedance is usually an innocuous load, some amps have difficulty as the impedance shifts. Remember that the nominal impedance of a speaker means average. Strong low or high frequencies result in large dips in impedance, increasing the strain momentarily on the connected amp. For some amplifiers, this engages the protection circuit, shutting the unit off.