Re: Marshall 1936 vs 1922?
The 1922 was designed to be an extension cab for open back 2x12 combo amps. The exterior dimensions were determined mainly for looks. It makes for a neat looking combo stack. Considering that the 1922 was designed for use with a 2x12 open back combo, the 1922 may well sound fine in conjunction with an open back combo.
The 1936 is essentially 2/3 the physical size and (cubic) volume of a full sized 4x12. It's intended as an alternative to a full size 4x12 for use with heads. It sounds closer to a 4x12, only not quite as loud, or such a pain to transport. A 2x12 also causes less resistance compared to a 4x12 among the "turn it down!" crowd.