Mind you, the speaker impedance is AC. Most multimeters will measure DC resistance, but not all will measure AC. Generally the DC resistance of the speakers will read a few ohms less than the rated AC impedance. For example, 8 ohms AC will probably read around 6 ohms DC, and 16 ohms AC will probably read around 12 ohms DC. It will be most accurate/safe/ideal if you are able to measure the AC impedance.