My idea for mapping Atmos -> Quad (and then CBS SQ matrix encoding), using a 7.1.4 Atmos setup (Figure 3):
https://www.quadraphonicquad.com/forums/threads/dolby-atmos®-faq.26939/#post-452222
Atmos C -> Quad CF
Atmos R -> Quad RF
Atmos Rs -> Quad RC
Atmos Rrs -> Quad RB
Atmos Lrs -> Quad LB
Atmos Ls -> Quad LC
Atmos L -> Quad LF
Overhead (nearest to RF, for example): 85% to RF, 5% each to RB,LB,LF, same for other 3 overhead speakers content.
The Atmos overhead content probably wouldn't sound like it's overhead though.
Kirk Bayne
https://www.quadraphonicquad.com/forums/threads/dolby-atmos®-faq.26939/#post-452222
Atmos C -> Quad CF
Atmos R -> Quad RF
Atmos Rs -> Quad RC
Atmos Rrs -> Quad RB
Atmos Lrs -> Quad LB
Atmos Ls -> Quad LC
Atmos L -> Quad LF
Overhead (nearest to RF, for example): 85% to RF, 5% each to RB,LB,LF, same for other 3 overhead speakers content.
The Atmos overhead content probably wouldn't sound like it's overhead though.
Kirk Bayne