All About Recording Sound To Camera & Camera Mixes
Before any shoot it’s always best to discuss any workflow requirements they may have; However on a large number of productions (especially in the commercial & corporate worlds) there aren’t any laid out specs for what they want delivered as a mix to camera other than they just want an audio feed to camera. In that instance what makes the most sense to deliver as a mix and record to camera?
There are plenty of productions where the audio mix delivered during production will be what gets used in the final product, goes out live to air, or inversely plenty where it’s just a reference for the editor and the recorded iso tracks will get used to create a new mix in post often including additional elements such as sound design and music. Taking the production style & content into account will determine what makes the most sense on a per production basis. Understanding your options as far as mixes and the pros and cons to each helps make informed workflow decisions under each scenario encountered.
Mono mixes are one of the most common types of mixes and for good reason. As production sound mixers, most of the sources we deal with are mono sources such as dialog. Summing whatever channels are working best in each moment gives you a ready to use mix on a single track. Another advantage to mono mixes is how easy they are to a single mix for everything from dailies to camera mixes, IFBs, VTR, & as reference audio for the editor to use while cutting the picture.
Dual Mono Mixes
Dual mono mixes are very similar to mono mixes except the mono mix is recorded to two tracks rather than a single track. This obviously uses more data as a duplicate of the same mix across two recorded tracks, but the advantage lies in previewing playback of recorded audio files or cameras that recorded a dual mono mix. With a single mono mix track on track one of a polywav file and the first isolation track on channel 2, when playing back the mix will come out of the left speaker and the first iso will come out of the right speaker. By recording a dual mono mix to both Track 1 & 2, when paying back files it will play the mix across both speakers.
For shoots with both mono and stereo content, the dual mono mix allows for seamless transition between them. The only difference between a stereo and dual mono mix is a mono mix has all the elements paned down the center and a stereo mix has paned element.
When dealing with stereo content it makes sense to deliver a stereo mix. While dialog will be mono sources, when dealing with music, ambiences, audience capture, etc, its pretty common for those to be recorded in stereo. Whether using stereo mic arrays, individual spot mics panned across the stereo field, or a combination of the two, delivering a stereo mix will ensure stereo content gets recorded to the audio and video files delivered.
Split mixes are simply when you hard pan sources to either the left or right track splitting them across the mix. A common example of this is Boom to the Left Track and Lavs summed to the Right Track. This practice originated in the era when you were limited to a two track recordings recorded either to a tape machine like a Nagra IV tape machine or directly to a camera such as was the norm in ENG betacam days.
The Case Against Split Mixes
While still commonly used by many sound mixers, I personally see them as a holdover from yesteryear that no longer make sense in today’s video production & broadcast environments. A split mix doesn’t give you a ready to use mix, and if summed together by some ignorant person down the line it will yield a phasey mess….nor does it yield a good experience for previewing files. What’s worse is I’ve seen broadcasts go to air and social spots (without dedicated audio post) end up with the split mix delivered as the final audio. The only redeeming aspect to split mixes fed to cameras is when dealing with a single lave and boom with one person on camera, the camera can serve as a redundant iso recorder. That said, I’m of the belief that it’s time split mixes die as a delivery standard.
Recorded Mix & ISO Feeds to Cameras
Camera feeds and mix tracks don’t necessarily have to mirror one another, and while delivering a mix recorded externally in the polywav files, the cameras could act as redundant recorders for iso tracks. Not every field recorder is going to have the routing flexibility to do this, but some allow outputs to mirror iso tracks on outputs.
On several live event recordings I did in 2021-2022 I was recording 4 channels of audio and delivering a mix for a quick turnaround. Since some of the content was stereo playback sources, I recorded a stereo mix to the polywav files as well as to A camera; However I was able to use the B & C cameras as redundant recorders by sending prefader isos to the inputs of those cameras. This was something production requested and was easily achievable with the routing of a Sound Devices 8 series recorder.
Only ISO Tracks
An option I would typically avoid is to only record iso tracks of the individual sources but not deliver any mix track. While certainly it can be a viable workflow, it does require addition work in post because you must create your mix there. Also because you aren’t delivering a mix to anywhere, it becomes a much more tedious experience for the editor, and previewing audio files will just play back the first two iso tracks.
Mixing with EQ, Compression, & Noise Reduction
With the advances we have seen in field mixers, it’s possible to use EQ, compression, & real time noise reduction to deliver better mixes in the field. While these aren’t something I would ever record to an iso track, this flexibility can bring huge improvements in quality to productions without dedicated audio post-production, live television, or live streams. Being able to do things like control the dynamic range of a mix, EQ out room resonances, and push down the noise floor makes a huge difference to the end result.
While all these things can be done doesn’t mean they always should be, and I’d advise only processing the mix track not recording isos with any sort of processing. The tools available in post give far more precision than is possible in the field in a much more accurate listening environment. It’s a great solution when there isn’t dedicated audio post, but it’s not a replacement for that.
When previewing audio or video files on a computer, whether straight from your operating system’s file browser or in a nonlinear editor, they will play the first two track of audio out of the left and right speakers respectively. For obvious reasons when playing back a file you just want to hear the mix track. For this reason I’m of the opinion that more often than not delivering dual mono or stereo mix tracks depending on the content makes the most sense. When you choose to only have a single mix track or no mix track, than previewing those files leaves a pretty poor playback experience.
Protection From Ignorance
Often times we have no idea what happens to the files after we deliver media at the end of the day. While a good post team will make the best out of whatever they are delivered and will even define delivery specs going into production, not every post team is created equal. I’ve seen & heard plenty of mistakes that somehow made it to air or into the final edit. It’s unfortunate, but it happens. I once got multiple emails after a 6 camera shoot because they couldn’t find iso tracks but never bothered to sync the external audio 🤦🏼♂️ and the cameras only had a single mix track recorded to them.
Because of these instances, I’m of the opinion that you should minimize the damage that can be done by ignorance down the line. This is another reason why on many shoots I default to the dual mono mix fed to camera, because if they just use what’s fed to camera and my mix is whatever sounded best, than what ends up in the final product will still sound good!
Hardwired vs Wireless Camera Audio
The reliability and sound quality a hardwired mix offers is pretty unbeatable. Whenever possible its best practice to hardwire mixes to camera. Wireless camera hops are a great solution for when camera movement or run and gun shoots happen. There are also varying degrees of audio quality from wireless, from broadcast quality to little more than reference audio for the editor. Understanding the context of the production, and what level of quality is needed when sending audio wirelessly to camera is important. For things like reality TV you may not need amazing fidelity recorded to camera just an audio reference coupled with timecode, however something like a ENG live broadcast you will need a higher quality camera feed.
On Camera Mics
When shooting with multiple cameras it’s not uncommon for the A & B cameras to separate especially on documentary and reality TV shoots. When a camera separates from the production sound mixer, while primary dialog may not be a priority it may still be important to have some audio even just for ambient sound. Many time on these types of productions the camera package will come with a shotgun mic on camera already, but other times this will fall onto the sound department to provide them. When I do provide on camera, I try and match those to my boom mic (Typically a DPA 4017) as the quality of sound will be much closer and allow for cutting between the two mics much easier.
Conclusion: My Approach To Mixes
Obviously if there is a predetermined spec from the client follow those first and foremost. When delivery specs aren’t specified beyond wanting audio to camera (which happens a lot), I usually default to a dual mono mix unless in a production’s needs justifies an alternative workflow. I think split mixes are a bad choice and I never deliver split mixes unless specifically requested. They are a hold over from another time and should not be relevant in today’s production environments. Ultimately it’s my job to make things easier for those down the line from me whether or not there is dedicated audio post production. In most circumstances the dual mono or stereo (if there is even stereo content) mix has the most pros and least cons compared to the other alternatives.