The 1975 altec parts reference chart shows the 9849A using the 23744 diaphragm in the 23746 driver ( oem 806-8A ) .

39

The 9849A monitor is found in the following catalogue ;1

Specifically, here's the page ; 40

The 604E is also featured in the same 1971 catalogue ; 41

This info suggests the existence of the 23744 diaphragm was well established before the 604-8G was released .

All other references for the 806-8A ( or 806A ) show that the 21597 ( or 20275 ) diaphragm was stock ( somewhat shooting down in flames, my previous conjecture ) .

<> EarlK