I thought the 18s had something like an early version of the KEF B139, though squarer, and without a standard basket - I remember pictures of a plywood or particle board piece with the magnet mounted on it, with the piece being mounted either to standoffs or to the cabinet itself.
The 18a clearly is a different speaker, without the KEF(ish) components, but yours looks very different from the one at the beginning of the thread.
The 18a clearly is a different speaker, without the KEF(ish) components, but yours looks very different from the one at the beginning of the thread.