The Pro Producer’s Guide To Headroom and levels
How loud can you go? Where’s your head(room) at? Why do you have to be careful with levels? Here’s our guide to signal-to-noise ratio, gain staging, headroom and a lot more as we continue our Back To Basics journey through some of the first principles of music production…
The world of music production is often about making things bigger, pushing the envelope and getting everything ‘on the limit’. It’s clear, then, that in the wrong hands your track could be heading into the danger zone. The world of digital audio levels is an unforgiving place that, unlike the warm analogue love afforded by classic gear, will shred your track and turn it into nonsense if you overstep a single dB mark.
So here’s the trick: give your track lots of digital space (known as headroom) to manoeuvre in, build signal chains (known as gain staging), that allow you to add sounds together (known as summing) in a pleasing fashion while keeping noise low.
Digital headroom is the breathing space we leave in a track, as opposed to trying to push all our levels as high as possible. But do peak indicators matter? Is it OK to clip channels? How do you set the master output level? We’ll be answering these questions and more. There are two major aspects of digital headroom we need to look at: recording and mixing.
If using summing stages and effects during production, consider their effect on headroom
Recording is straightforward: you get an analogue signal into your DAW as a digital recording, so for example, you sing into a microphone and it’s recorded in your computer.
Next comes mixing, which in this case doesn’t just refer to the final mixdown process after composing and producing your track. Most electronic music producers mix as they go to some extent, so if we’re using summing stages and effects as part of our production technique we also need to consider the effect they’re having on headroom and the overall sound. Let’s start off with getting the sound into your DAW in the first place and see exactly how headroom affects recording.
The recording stage
Headroom is important from the moment you start recording signals. To understand digital headroom, let’s first look back to the analogue days. Most of us are now recording digitally, but we can still learn a lot from the analogue recording process.
Signal-tonoise ratio explained
All because tape had to be hit as hard as possible to avoid noise interference
It’s important to maintain the highest possible signal-to-noise ratio. In simple terms, this means keeping the signal as loud as possible while keeping background noise as quiet as possible. The perfect example is tape hiss. When music was recorded to analogue tape, a gentle hiss in the background of a recording was an inevitable side effect. Recording engineers learned that a certain technique could make it less prominent in the final mix.
If we record our tracks to tape at a relatively low level, the first thing we’re likely to do when mixing the recording down is to amplify those recorded signals.
But when we amplify playback from the tape, we’re not just boosting the signals we were trying to capture, we’re also boosting the tape hiss. That could add up to a noticeable background noise.
The solution is to record those signals at a higher level, meaning they don’t have to be amplified as much. We can then achieve the same overall mix at the same level with a lower level of hiss.
The same approach applies no matter what type of audio signal we’re dealing with. Most of us now record digitally, so tape hiss probably isn’t an issue, but there are still unavoidable elements of noise that exist in a nominally ‘digital’ recording setup.
Ultimately, you might be recording to a digital medium (your DAW and computer’s hard drive) but there are analogue signals along the way – every piece of equipment could introduce noise.
The general approach of most recording engineers in the analogue tape era was to hit the tape as hard as possible without overloading it, guaranteeing the signal-to-noise ratio was as high as possible. One principle to consider is starting with a relatively hot signal, making it quieter where needed rather than starting with a quiet signal and amplifying it along with its noise.
Whenever we amplify a signal, we’re amplifying every part of it. If we’re amplifying to compensate for a weak signal that could have been boosted earlier in the chain – before the introduction of unwanted background noise – we’re not getting the best signalto-noise ratio.
With so much equipment on the market it’s impossible to give a 100% foolproof formula for setting input and output levels.
Gain staging is a balancing act – it’s about juggling input and output level settings on each piece of equipment until you find what gives the best results.
Thankfully, it’s a relatively easy process, but one you should run through before you start recording. Hook up all your gear – whether it’s a synth into an interface or a complex chain of preamps, compressors and effects – start with a loud signal from your source, determine the overall combination of settings that give the cleanest sound, and then start the recording process.