Ok, so I've got two speakers. All I know about them is that they were made by Leslie and they are 12" wide. There is a parts number on the back - 33 5120 4 - but this number does not appear in any database I can find. So, how can I find out how many ohms these things are? They're pretty nice speakers, I want to wire them up in a home-built cab, but obviously I can't just wire them up and expect them or the amp to not be destroyed if I don't even know the impedance. Is it going to take some kind of expensive test equipment to find out?