RAM 1
The bass unit is a Dalesford 8 inch bextrene unit, and the hf unit is an Isophon hard plastic dome. In later production this was changed to an Audax soft dome unit.
There is a port at the top of the front panel (hard to see here), which is packed with welded drinking straws to provide low frequency damping.
RAM 2
The RAM2 was a 3 way reflex speaker, using two 8 inch 13 ohm Dalesford bextrene units in parallel, and a Peerless 4 inch doped paper cone midrange. The make of the hf unit escapes me at the moment, but may have been a Peerless.
(3D recreation)
RAM 3
The RAM3 used the same units as the RAM2, which was a scaled down version. This was designed before the RAM2, and derived from the first speaker I ever made, which used two KEF B200's for base units, and, whilst sounding good, had an awful impedance curve (two 8 ohm units in parallel) that some amps at the time didn't like.
(3D recreation)