Q: What is the best output to use for a stereo recording on the ML4000?
We're currently using the Local Monitor Outs at my church, but my opinion is that we should be using the main outputs as this is the purest signal.
A: Using the Local Monitor Outputs is a strange choice for a recording feed, not due to signal integrity (the monitor out needs to be a faithful reproduction of the output signal), but mainly for the fact that were someone to press a PFL or AFL button during the recording, the main output signal would be replaced by that of the monitored channel.
This is fine for a recording engineer to listen to a signal in isolation, but not great for a recording! Similarly, if the engineer chooses to monitor the 2-trk In source (for cueing backing music perhaps), this would replace the main output in the recording. Finally, if the talkback circuit is used for communication, the monitors also go dim, again, which would affect the recorded levels.
Depending on the recorder in question, for most applications, we would recommend the 2-TRK Out connection for recording. By default, this signal is taken after the main faders, so any mixing fades on these faders would be present in the recording. By moving internal jumper positions, however, this signal can be sourced pre-insert (before any external EQ or compression), so would by definition also be pre-fader, and pre-mute (fader movements and mutes not recorded).
The best use of the local monitor circuit would be for the placement of a wedge monitor or monitor-pair for stereo so that the mixing engineer can hear the auxiliary sends (for musicians monitors etc. in the same medium that the musician would, rather than through headphones, which is not always as faithful).