Here's a question I shouldn't need to ask. Can anyone assist in determining whether the impedance of this old 15" speaker is 8 ohms (so I can determine whether it is safe to use as an extension cab for a WM12)? It was installed as a replacement in a 1x15 cab over 20 years ago by a local music shop (long since defunct). The cabinet was a cheap, well used Univox/Unicord cab, and there was no discussion or consideration of replacing it with the same model as the original. There also was no discussion (and it didnt even occur to me to ask) about impedance. At the time I was using an Acoustic 150b head (still alive and kicking), and I would have told them this. I believe but I couldnt swear that I asked for an Eminence speaker. I do recall I selected one of the more expensive options. I never checked to see if they actually installed what I had asked for. There is no manufacturers name or trademark on the speaker. The following number is printed in white on the black steel frame: U4100-4A67-7709. There is a white tag on one of the spokes of the frame, on which the following number is written in ballpoint pen: 163-772. The magnet is a 5 by 5 square. The magnet itself is about 3/4 thick. Bolted on the back of the magnet is a square of white dull metal, either aluminum or zinc-plated something. I tried putting an ohmmeter across the leads, but I got a reading of zero resistance. (I obviously dont have a clue about what I am doing.) If posting a picture of the speaker would help, please let me know. Any assistance would be greatly appreciated. (P.S. - If speaker technology has advanced so far that it is crazy to fool around with a speaker of this vintage, please let me know.) Thank you.