In the days of analogue live sound, we were generally encouraged to keep our signals as hot as possible. These, of course, were the days when analogue saturation was common, pleasant-sounding, and very much part of the character.
Today with digital live sound, driving anything close to 0dBFS has the opposite outcome completely. It will result in digital clipping, where part of your audio is simply chopped off, resulting in a generally unpleasant, harsh-sounding audio for any signal that isn't given enough headroom.
When it comes to recording live, even if it's just for the purpose of virtual sound-checking, recordings are often made by the FOH Engineer. But it's not quite as easy as it may seem to wear both hats and keep your ears on the live mix and an eye on the levels of what's being committed to disk.
The good news is you don't have to be a grammy-winning engineer to fill this role. If you find yourself in these shoes for the first time, here are my top 10 tips that will guide you to a successful outcome.
1: Do Your Homework
This is more about seeing the band or artist you're about to record than preparing a track list and template. Listen in both sound checks and performances. Look out for particularly dynamic sections on vocals, guitars, synths, and drum pads!
You don't want to have something unexpected destroying your recording or forcing you to re-record certain sections later in the studio. Make a note of anything that stands out so you can ask for a rendition during sound check. Even better, do a test run of the show and monitor closely.
Check where things can be improved or problems solved. Make sure you're armed with all the relevant and important information, and above all, never delete anything until the project is completed. You never know when that little piece of magic will reveal itself.
Where possible, try to record in the later part of a tour instead of the early stages. Performances have a tendency, like wine, to improve with age!
2: Headroom, Headroom and Headroom
This is probably the most important word you will ever hear with regard to digital recording, but it's magnified 10-fold when it comes to live recording.
This is often why location, film and TV sound crews are so well respected; second chances here are few and far between. As a guide, an RMS of -18dBFS is considered the 'sweet spot', but when it comes to classical and operatic performances, I refer back to point one.
3: Headroom: Beware The Adrenaline Factor
Unsurprisingly, one of the biggest stumbling blocks to faithfully capturing the opening few numbers is something I call "the adrenaline factor". Again, this is another reason why leaving enough headroom is so vital.
You can spend an hour or so line checking and rechecking every instrument and voice only to find as the band launches into the opening number, everything is immediately 3-12 dB hotter than it was in sound check.
Now, this is not always the case with some genres, but it is true for the more traditional rock band formats. To avoid falling foul of this phenomenon, refer back to points one and two.
4: Pay Close Attention to Gain Staging
Again, this is part of ensuring you have enough headroom for your recordings to maintain as much of their dynamic range as possible, thereby providing you with the best possible audio recording going forward.
This is especially true if you're recording with Pro Tools, Universal Audio's Luna or other DAWs that allow you to use console emulations and Plugins of classic analogue studio outboard gear. You must check every stage to ensure the gain isn't creeping back up (or down) as it passes every enhancement on its way to your hard drive.