Capturing Audio for Video
Since the audio on our Celebrate With Family service video uploads turned out pretty nice and the fact that we get queried often about it—let’s give our audio recording path a brief run-down, “nerd-speak” style. Enjoy!
By the way—if you have any interest in the house PA, check out this previous blog post for an in-depth look... Now here’s the down-low for the recording side:
A pair of RODE NT1 mics hang from the center of the catwalk in a stereo pair positioned 90º off axis aimed towards the back of the room. This puts them almost exactly center of the room allowing them to pick up a fairly nice audience feel with a decent amount of rejection for what is coming out of the PA. Each of these mics hits one side of a Midas XL42 mic preamp where I’ve got a smidge of EQ and high-pass filtering going on. Hitting the Midas pre’s really does wonders for these mics as these completely make the difference in how the whole mix comes together...
This is a matched set of AKG 414’s in the back of the room that are positioned on the camera deck (we call it the lanai) directly in front of and slightly below the audio mix platform. These are set to pretty much duplicate what I hear while mixing; they are set to a cardioid pattern and aimed L/R towards the PA just a wee bit off-axis.
Stereo mix straight out of the primary Midas Heritage 3000. No magic potion here other than Midas awesomeness...
From here, the stereo board mix and the two audience mics hit their own individual inputs on a DBX 4800 where they are combined to a single pair of outputs—there is a small time correction done here that delays the board mix to match the audience mics. This newly combined output is now what becomes our “board mix” and is sent to all of the other parts of the facility including CCTV feeds, lobbies, overflow rooms, CD duplication, DVD recorders (for archive and backups) and is used for all of our radio show and podcast content. This is a really effective way to make sure that everywhere this mix goes receives a nice dose of ambience and audience levels which translates MUCH more dynamically and true than a typical dry board mix.
For our video capture, the board mix (now with the combined audience mics) is sent digitally from the 4800 directly to a Mac Pro running Final Cut. The room mics are converted to digital as well and hit Final Cut on two additional channels. So all of our video content has audio that is comprised of only these four inputs. Once an event is completed and any minor video editing is completed—an OMF is sent over for audio leveling and mastering in Pro Tools. The basic use of this step is so I can maximize the volume output of the overall mix prior to hitting the web and it gives me a chance to adjust the levels of all the segments—bringing the speaking segments up to match the music a bit more, limiting the mix as a whole, a bit of overall equalization and polish, etc. I also correct the time delay discrepancy between the board mix and the room mics (the audio information arrives LATER to the room mics and to Final Cut than the board mix so it requires a bit of time adjustment). This mastered stereo mix is sent back over to Final Cut where it’s combined with the video file and exported and uploaded.
So it’s a pretty basic setup—no multi-track recording or mumbo-jumbo going on here—just a simple capture setup that gives us a realistic version of what our room sounds like.
What makes this work so well is the quality of the house mix—plain and simple. We do get quizzed now and again about how we capture such a real sounding house mix and it really comes down to how it’s mixed when we’re in the event. Bottom line: if I blow it, that’s what we get and I have to live with it—so since that is unacceptable to me on about a billion different levels, I strive to make every mix stellar (mind you—this is a lofty goal for me somedays).
Here is the obligatory full disclosure: How I get a good board mix is derived a great deal from self-preservation... Yep, self-preservation for yours truly. Spending plenty of years on the road getting beat up nightly by the quality (or lack thereof) of my board mixes for whatever band du jour I was traveling with—I started trying to make my mixes a bit more representative of what I KNEW these rooms and bands sounded like. But you can’t really explain that to a rock band after the fact without coming across like a weenie... So I started adding the little extras like audience and room mics into the board mix on the sly but it really started making my mixes sound MUCH more dynamic and REAL. And you would be completely surprised at how few people caught on to why these mixes started sounding so much better all of a sudden...
We’ve spent the last few years exercising these principles to improve the mix captures at COTM with great results. As with anything audio or design related—everything is subjective and has to be adapted to each specific situation and scenario but for us this has been a fairly uncomplicated way to get a realistic representation of what’s happening for our live events.