Here is a video on how to read the impedance of a speaker. If you take a reading of an 8 ohm speaker you will find that it does not read perfectly at 8 ohms. According to Anthony Lucas at Eminence Speakers “When a speaker is labeled 8 ohms, it is actually a nominal reading. An ohm meter measures the resistance to direct current (DC), but music is alternating current (AC). A speaker’s impedance to AC depends on frequency and the nominal rated impedance is sort of an average impedance over the useable frequency range of the speaker”. So do not panic if you wire up a multi-speaker enclosure and it reads below what you think it is going to read. Just observe proper polarity, hook up your speakers and ROCK!!!