Martin Audio C8.1T - Manual (Page 7)

2-way ceiling loudspeaker orientation
Make sure that the C4.8T and C6.8T swivel-tabs do not coincide with
the C-bracket gap.
Loudspeaker in place.
Note swivel-tab positions before fully tightening
It is permissible for one of the five C8.1T swivel-tabs to coincide with
a C-bracket gap in order to maintain driver orientation.
All material © 2007. Martin Audio Ltd. Subject to change without notice.