mrtcat - yes quite right, 4 pin speakons are designed for feeding separate high and low signals to a speaker cabs via a single 4 core cable so bi amp bass amps e.g. a GK would utilise this system, my problems with a 4 pole speakon maybe just be age and use and could have occurred on an old 2 pole plug, but I wondered if failure is more likely due to the twist action where a weak spring trying to apply pressure to 4 contact fingers may leave the two you require to not get the pressure required to make good contact, I have just got a bit superstitious! about it and feel if there are only two contact points those are the ones that will meet up when i twist it into place.