[Arran]

One thing about the field coil speaker on this set, the rear bracket is bolted in place so you can easily remove it to repair, or rewind the field coil. You just unbolt the bracket, and the bobbin with the field coil should slide right off without disturbing the voice coil, cone, spider, or anything else. Stromberg Carlson used to manufacture their own speakers, so they tended to build them a little better theme with better quality materials, which is more then I can say about the plastic knobs they used.
Regards
Arran