I am trying to measure the impedance of a 2x12" cabinet wired in series with 2, 8-ohm speakers. Using a Fluke voltmeter, I am getting 26 ohms. I had thought that this type of measurement would yield a result that is somewhat less than the expected 16 ohms and not more. Any suggestions? Using the same voltmeter on an 8 ohm 4x12 give 6.4 ohms and on a single 1x12 with an 8 ohm speaker I get 5.8 ohms. All measurements are taken without any signal using a plug in the speaker jack.