How should I connect my audio interface and my mixer together to communicate with my PC? I Basically want to record through my mixer and use my audio interface as the sound card. where does my monitors plug into, the mixer or audio interface, etc??
When recording, the signal passes through the mixer into the audio interface.
When playing back the recorded signal, the signal passes from the audio interface into the mixer and from the mixer out to the speakers.
The monitors/headphones are connected to the console, not to the audio interface. Converters are kind of like EQ filters and it is not uncommon that the signal passes one ad-da-ad cycle and one da-ad cycle throughout a project, so hence 5 times of conversion can add up, but you compensate naturally so therefore whatever that ends up on the last ad is what it becomes, that's done with a transparent mastering converter. But because the last ad is so critical, it is wise to feed the signal to two other totally discrete signal chains besides the standard analog one, those are monitored digitally, meaning that the signal passes an additional ad-da route for the purpose of getting the color from it. If you are very serious you do this both during mixing and mastering, so you might have engaged 6 totally discrete signal paths on a production, 2 analog, 4 digital. But it is the 2 analog ones that are most important. All of the converters must have great headroom.
So what you want to achieve is to have the product of all of these signal chains as close to the truth as possible, so that even when they create an expanded view of the audio, that window is narrow enough relative to a true flat frequency response (audio dim. 1) and the signal that passes it is close enough to the center point of them all (audio dim. 2). Here is where the choice of converters and especially acoustics come into play, because both of the audio dimensions are negatively impacted by using poor converters in a very dense inaccurate monitoring environment. When you align the converters, the monitors, the acoustics well and the audio well against that, you get a great final result.
So in other words, when you work in the hardware domain, it is not only that you get more true audio processing in itself, but you work within a more true audio window as well. The combination makes the difference, especially when on top of that you are able to reference multiple sources at the same time and can adjust towards their combined sweet spot. These systems need to be time synchronized, not all choose that advanced monitoring route. Some prefer a more simple route by having just very high transparency in the final ad and then they monitor from their analog console. But I recommend the route of running multiple discrete monitoring paths and do so in various monitoring configurations for checking various things... When it comes to the headphones there are techniques of downgrading the signal on purpose at the connector, providing you an additional dimension of audio/perspective on every headphone set, not to mention that you can also combine multiple open or semi closed headphone sets both by using one can from each on each ear (then you can also use closed back cans or a mix) or by placing one of the sets around the neck. This combination of going this advanced with monitoring of course pays off, especially when you know what monitors and headphones to engage.