Usually the MixPre is serving as an audio adapter and sometimes as a recorder. We run Mics (usually one or two) into the MixPre, then run the MixPre's stereo out into the camera - single channel summed for one mic or two separate channels for two mics.
Sometimes I'll record on the MixPre, but often I won't - I'll just use the audio the camera recorded from the MixPre's stereo out. There is a small increase in sound quality when using the MixPre file compared to using the camera audio (which was fed into the camera with the MixPre). Even when I record with the MixPre, I will still feed the audio into the camera for a clean sync track as well as for archival purposes - where I work, there's no guarantee the off-camera audio file will exist in years/decades to come, so a clean audio track is always good.
The advantages of adding the MixPre into my workflow are chiefly:
- Excellent audio level meters that are easy to read and see at a glance. The rings that light up around each channel knob let me easily check levels when I'm working solo.
- Real hardware limiters, so my audio doesn't clip. Yes, you can hear the limiters if you're hitting them all the time, but they're there to buy insurance, not be idiot-proof.
- Excellent knobs for setting levels on-the-fly and making adjustments during an interview or shoot.
- Really good audio quality - the preamps are wonderful, and they have enough gain to use an SM7b for voiceover work. The audio quality style reminds me of a Grace M901 preamp - very, very clean in character.
- Very scalable for a variety of jobs. I use it for a handheld audio recorder as well as for video production work.
I have not yet recorded three channels of audio, but if I did, then, yes, I would have to record onto the MixPre only or make do with a mixdown.
It's honestly a piece of gear that just makes me happy whenever I use it. But be aware - because it is very scalable, there are a
ton of ways to set it up. But once it's set, it's good to go.
And I'm not holding out for a native camera option, unless it were to be battery-grip-style. While the MixPre requires extra cables and whatnot, that's just the way of video production, IMO.