Time alignment will be critical during mix down when we sum the audience mics in the mix. The most efficient method I know is to record-arm all the audience mics, solo the snare drum through the PA, and give it a wallop.
Now all our audience mics have a convenient transient, which we can use as an impulse response to align the mics in the DAW (editing software) by visually aligning the wave forms. This is faster and more accurate than using tape measures, laser distos (distometers), or software sample delay, in my opinion.
By the way, before you hit “record” on the DAW, do yourself a huge favor and name all of the tracks in the software. When you start to record, the software will then generate properly-named – rather than just sequentially numbered – audio files. This can save hours of frustration during the editing stage on big projects.
Getting It In Shape
My mixdown strategy is to use the isolated direct lines from the stage mics to create a clean, full mix, just as I would in the studio. Studio engineers utilize a variety of different reverbs – often a combination of rooms, plates, and halls – for different mix elements. I do the same thing for live recording, but I route all of the reverb returns through a VCA, which will come in handy when we add in “venue” reverb later.
Audience mics are next, enough to bring the audience into the mix, but not wash it out or cloud it up. We can ride levels up between songs or when the audience becomes very responsive. I feel it’s best to do this by hand, writing a Latch automation track, rather than by using gates, which, to my ear, can sound unnatural.
Be on the lookout for what we call “wild material” – cheers, applause, and especially applause endings that decay cleanly without a band member tuning or speaking over it. This comes in handy if we later need to edit ourselves out of a tight spot.
At no point should a live recording be silent – some engineers use a looping track of room noise and audience noise – so we’ll need samples of each. Audiences make more noise after uptempo songs then after slow ones, so we’ll want wild material of both. (For more about editing and mastering live albums, see Bob Katz’s excellent “Mastering Audio: The Art and the Science,” which I consult often.)
I aggressively high-pass the audience mics, as high as 150 Hz or 200 Hz. Venues are boomy in the low frequencies, almost without exception. Remove this, and the mix tightens up. We don’t want a change in LF tone when the audience mics are ridden up and down, plus audiences are human and humans aren’t contributing anything worth keeping below 100 Hz. Get rid of it.
If we want some “space” on LF from the kick drum and bass guitar, we can use some reverb of our own. It’s humorous to me that some engineers will balk at high-passing the LF noise out of an actual room recording but will high-pass an artificial reverb return without a second thought. It’s the same thing! LF mud has ruined more than a few live recordings – don’t let it be the death of yours.
Returning To The Scene
OK, now we have a nice clean mix that hopefully minimizes the contribution of the actual, non-ideal acoustic environment. Let’s go ahead and put it back into an ideal one of our own.
We’ll need a reverb that at least somewhat resembles the original venue – a club gig should sound like a club, and an arena gig like an arena. But we have a lot of leeway here, and we can manipulate the reverbs parameters to suit our purposes. I pay particular attention to pre-delay and the frequency response of the decay. Convolution reverbs will earn their keep in these applications.
We can really tailor the “venue reverb” to make it work for us, not against us – maybe exaggerate the space for a ballad and then dial it back a bit to tighten up an uptempo song. This is why we put “studio” reverbs on a VCA – we can easily balance them against the “venue” verb dynamically to control the overall reverberant characteristic as we subtly manipulate the room sound. If we’re pushing the venue verb a bit on a slow number, it’s easy to pull back on the other reverbs to keep our mix from washing out.
To sound realistic, I use at least one discrete reflection, basically to give the “virtual venue” a back wall. (The audience mics won’t capture a clean rear-wall reflection because they’re time-aligned to an arrival from the front, which means they’ll scatter on arrival from the rear.)
I employ a basic single-tap delay with highs and lows rolled off, and here’s the secret sauce: don’t route the delay to the main mix, but instead to the “venue” reverb. Reflective paths are reverberant, too. The “dry” delays we’re used to using sound cool as an effect but aren’t convincing in an acoustic sense.
It doesn’t take much of a reflection to imply the acoustic space, so keep it low. And we also don’t need everything in it – surprisingly, just the vocal is often enough.
Transient instruments like drums sound bad coming off the back wall, and I’ve found they’re usually not necessary to create the illusion. Listen to the excellent live album of Billy Joel at Shea Stadium, particularly “Miami 2017 (Seen The Lights Go Out On Broadway)” and study the single “rear wall reflection.” It’s very deliberate, and works well.
This is another example of our electronic approximation being superior to the real deal – I’ve never encountered a rear wall that only reflects vocals.
This is just a new iteration of the old debate over whether reinforced sound is natural. It is, but in a complimentary way – without reinforcement, artists would need to scream to be heard. That’s unnatural. With “unnatural” reinforcement, they can sing and speak in a natural way. The “unnaturalness” we bring to the table enables natural behavior of the artists.
So, in my view, a good live recording is an extension of the same concept. Only by departing from what a listener would have heard if they were actually there can we make a listener feel like they were actually there.
And for the record, when it comes time to ring in the next New Year, I’ll be quite content watching the ball drop – on TV.