Professional Mastering - Analog & Digital
Professional Mastering
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I could spend hours talking about different saturators, compressors, reverbs, and all of the small nuances that make them unique or beneficial to a project.
But one effect that doesn’t get the admiration it deserves is Gating.
See, I didn’t even put Gating in the title of this video, because I knew if I did, a lot of people would think, ‘I know what that does, I don’t really care,’ but its benefit to mixing goes well beyond what most people realize.
Its most common use is noise reduction, but it also greatly improves phase relations, controls the frequency response, increases the perception of dynamics, and makes all of the processing you introduce later in a chain sound significantly better.
So, let’s learn more about The Most Underrated Part of Mixing
Watch the video to learn more >
If you’ve ever mixed a multitrack instrument, you’ve likely used gating to isolate specific elements.
This is especially true with multi-tracked drums.
I have a session here with 17 tracks for one performance, which is about what you can expect for most professionally recorded drums.
The primary challenge here is finding how to control them while keeping everything cohesive and in-phase.
If we zoom in on the waveforms, we’ll notice small variations between each track’s peaks and troughs.
This is to be expected - each microphone used has a different frequency response, or is closer to a certain part of the drum set than another.
Also, the distance between the microphone and the instrument affects when the sound arrives at the microphone, since sound travels, it doesn’t arrive at the mic instantly.
But then there are surprisingly common extreme examples - for instance, you’ll notice that this Crush mic is just about completely out-of-phase with the room mics, the overheads, the snares, the kicks, and so on.
If I amplified this Crush track and didn’t fix its phase, it would cause significant phase cancellation and seriously hinder the mixing process.
Instead, I’ll flip the phase so that it adds to the kick, snare, and so on, instead of cancelling them out.
But what does this have to do with Gating?
Well, you notice that between the transients of a close-miked instrument, like a kick drum or a snare, we still have signal. This signal is the entire drum set, albeit quieter than the close-miked instrument.
More importantly, this signal is often if not always, conflicting with the phase of the overheads, the room mics, any other microphone that captures the set as a whole, and the bleed from other close-miced aspects.
So, say I’ve ensured the snare is aligned with the overheads, and I think, ‘we’ll the phase is controlled between them, I’m fine.’
In truth, the phase is aligned for the snare’s transient - but it’s not aligned for everything else that the mic picked up.
So, just like the crush mic that would’ve caused phase cancellation, I need to fix this issue if I want cohesive and professional-sounding drums.
This is why gating close-miked instruments is crucial if you’re mixing a multitracked instrument.
What you use is up to you, but I like this deBleed gate by THR, since it’s designed with drums in mind.
In other words, the transient that’s in phase is retained, while everything that’s out of phase, the undesired bleed from the rest of the drum set, is kept to a minimum.
I’ll use each of the 3 algorithms for their related sources, then I’ll use the analyze feature to see what’s recommended, before making some adjustments as needed. Or I’ll start with a preset and move from there.
With this simple step, one that’s often forgotten about, I’ve just significantly improved the drum sound. Not with saturation, eq, or reverb, but by keeping the multiple recordings from fighting with one another.
So, let’s listen to the drums before and after fixing the phase.
First, we’ll check out the drums as they were recorded. Then, I’ll introduce some corrections to the phase, like what I discussed earlier with the crush mic.
Lastly, I’ll introduce THR’s deBleed plugin. Notice how we’re not just isolating instruments; we’re greatly improving the phase relationships between the various recordings, which improves the drums as a whole.
Watch the video to learn more >
Gating is, in many ways, a dynamic equalizer.
When a snare hits, particular frequencies are present. In between the hits, different frequencies are present. The actual hit, sustain, and release of a snare may cover the majority of the frequency spectrum.
But the gaps may have room ambience, electrical noise, and as we covered, other instruments with their unique frequency responses.
When this gap is attenuated, or gated, the frequencies that occupy that portion of the snare’s recording are attenuated.
Say in between snare hits, there’s noise from 5kHz to 12kHz peaking at -40dB. That would have a large impact on the sound of the drums as a whole, and, in turn, the mix.
Gating attenuates this section, meaning that noise no longer contributes to the sound of the drums or the mix.
This may seem like a small change, but if it’s performed across multiple tracks and multiple instrument types, it makes a huge difference to a mix’s frequency response.
Next, let’s say I plan on compressing this same snare.
With a compressor, I reduce the peak level. Then, to make the snare sound full and detailed, I’ll apply makeup gain. What we’ve really accomplished here is we’ve increased the ratio of lower amplitude signals, relative to high amplitude signals.
Things that were masked by the snare’s peaks are now easier to hear.
But what if we forgot to gate this snare? Then, all of those unwanted frequencies, noise, unrelated instrument bleed, and so on, are also amplified.
A huge part of mixing and mastering is taking those quiet details and bringing them forward to create a complex sound.
When we don’t gate, the tracks become noisier and noisier with each additive processor.
Now, remember what I said in the first portion of this video - that gating reduces phase cancellation.
Following the same logic when applying compression and make-up gain, these quieter, out-of-phase elements will become louder. Furthermore, the in-phase aspect, the transient, is reduced.
So, if we don’t gate, and then we amplify quieter details via post-compression make-up gain, or maybe an upward processor, we’ve greatly and negatively affected the phase relations.
Do you get why I think this processor isn’t given the attention it deserves? Its absence can greatly reduce the quality of a mix and the subsequent master.
Let’s listen to our drums again. First, I’ll include a good deal of upward processing or amplification of quiet details. Notice an excess of noise and how, even though they’re louder, they sound thin.
Then, I’ll enable gating before any upward processing. Notice how it greatly improves the perceived loudness, the clarity, and cohesion amongst the multiple tracks.
Watch the video to learn more >
This last part is probably the best known or discussed, but it’s almost always downplayed.
Again, let’s look at a snare. Let’s say the snare peaks at -3dB. Meanwhile, the noise between snare hits is -50dB.
The dynamic range in this situation is 47dB.
Now, let’s say I add a gate and it silences the noise between snare hits. Although there’s an argument that we now have an infinite dynamic range, let’s say the new dynamic range spans from the threshold for hearing and -3dB.
This would be a dynamic range of about 120dB give or take 10dB. So, with a simple gate, we’ve increased the dynamic range of this track by about 70dB.
Just like before, this is a cool albeit small change when taking the full mix into account - but when applied to 10, 20, maybe 30 tracks depending on what’s present in the recording, we’ll likely end up increasing the dynamic range of the full mix by about 30-40dB.
Now factor in the limiting or clipping that occurs during most mastering sessions - the quiet details of the tracks that we intentionally left ungated, maybe the overheads or room mics, are now the noise floor.
Instead of having this dense noise floor that's been amplified to -40 or -30dB, we now have this massive range that creates a wonderful sense of depth.
For the sake of demonstrating this idea, I’ll apply heavy limiting to the drums. At first, I won’t apply gating. Notice the lack of depth due to how much we’ve amplified the noise floor.
Then I’ll enable the gates. The perceived loudness remains the same, however, now we have an impressive depth.