Thanks guys, I suspect it must be a mix down if using four channels. In reality I’m only really going to use two mono channels (shotgun + lapel) so wonder if the line out to camera will result in the same quality as syncing later in post? (ie 1 mono per stereo channel) I guess if it did people wouldn’t bother with post syncing! Have also read the Sescom cable isn’t necessary with the 6d.
Anyway the big question is, will the quality be that much better recording with the external recorder, or is better to swap the DR-40 with a Beachtek dxa-slr pro / mini etc and skip the syncing bit? Or will the DR-40 effectively work in the same way as the Beachtek if providing line out to the camera?