Sonible smart:gate

Just why would you make the humble noise gate ‘smart’? Sonible asked that question, and this plug‑in answers it!

Sonible were pioneers in the use of AI and machine learning in DAW plug‑ins, and in recent years they’ve delivered an impressive range of processors that make use of that technology. Their latest offering is smart:gate and, as might now be expected from the ‘smart’ series, this looks to apply the benefits of AI technology to the noise gate.

A traditional noise gate essentially opens (to let audio through) and closes (to block it) in response to the incoming signal level — the user can usually set the threshold at which this open/close state changes. Most modern gates, whether hardware or software, also allow the user to control details such as how quickly the gate opens, the minimum time during which the gate remains open and the opacity or floor of the gate when closed (if it’s only part‑closed, it brings the signal level down to that floor). Of course, smart:gate can be used in this fashion — in fact, as a conventional gate, it’s very well specified — but of course this gate is also smart. So let’s see what else it can do...

Context Is Everything

One thing smart:gate offers that’s out of the ordinary is a ‘content aware’ mode. As shown in the main screenshot, Sonible provide a number of common target profiles, and once you’ve selected one of these the plug‑in analyses a short section of the incoming audio. It attempts to identify, within that input signal, a match for the selected target and then configure initial settings — once done, the gate should open only when the level of the selected target exceeds the threshold. Other sound elements within the signal will not trigger the gate. And for many sources, this might be all that’s required.

smart:gate analyses the incoming signal for the information that most closely resembles the chosen target profile — it will only open when it detects those sounds in a signal.

As with all Sonible’s smart plug‑ins, the UI provides plenty of graphical feedback that enables you to visualise exactly what the gate is doing. When working in its content aware mode, this includes identifying exactly which parts of the input signal’s waveform are identified as a match for the selected target, as well as the state of the gate as it changes over time. If you feel the need to fine‑tune the conventional gate controls (attack, threshold, release and hold, for example), this visual feedback is particularly helpful; those controls operate exactly as you’d expect, but only on the selected sound. It’s a very neat trick and in general it works very well.

Bells & Whistles

Of course, while Sonible’s AI assistance can do the heavy lifting, you might still wish to dig a little deeper, in which case there are plenty more options you can explore. For example, with the gate already targeting only a specific sound type, the Level Bias control lets you change the emphasis placed on input level of that source in controlling the gate. A low Level Bias setting can suit sounds without a particularly strong transient (eg. vocals), while a high Level Bias lets the gate follow sounds with stronger transients (such as drums) more effectively. The plug‑in offers a Mono/Mid vs Side switch, to change how the detection process responds when using a stereo input, and you can also switch between gating and ducking modes. The latter can be used with the side‑chain input and, for example, would make it very easy to duck the level of a backing track using a send from a voiceover into the side‑chain.

The Level Bias facility offers a means of fine‑tuning the gate’s response to suit different sound sources.

Perhaps the most interesting addition is the Impact Controls. These can be adjusted at the base of the UI and a full panel can be popped open to provide a more graphical tweaking experience. The Impact slider controls the degree to which the gate actually shuts when the target signal isn’t present, with 100 percent being fully shut and 0 being fully open (essentially, the same as bypassing the plug‑in). While this capability is found on lots of noise gate designs, the three further controls (band suppression for the low, mid and high frequencies) are not. These essentially operate to control the release time of the gate in each frequency band (higher values force faster release times) and you can also adjust the crossover points between the three bands. These controls require a little familiarisation time, but, usefully, you can solo a band to hear what’s going on and they do provide some very interesting ways to finesse the tonality of your signal.

Finally, amongst the other features, it’s worth noting the eight State slots at the top of the UI. These let you save different settings in a single instance of the plug‑in and easily toggle between them as you fine‑tune your settings. All the plug‑in’s key parameters are available for automation, but not these — it would be very cool if you could also automate the State number, to quickly switch between full configurations that suit different parts of a performance.

Smart By Name, Smart By Nature?

For those who deal with a lot of multi‑channel acoustic drum recordings, smart:gate could probably pay for itself very quickly in time saved. It can be tricky when miking a kit not to end up with significant bleed on your main close mics. That can mean, for example, that your kick is pretty loud on your snare recording and vice versa, and that can leave you with less control than you’d like. With its content-aware approach, smart:gate offers the potential to isolate each drum very effectively.

I realise, of course, that a little bleed can often help to give a drum recording its sense of coherence — you won’t always want to remove it entirely — but with better isolation of your kick, snare and hat sounds, it’s so much easier to dial in your EQ and compression on those elements. Whether you want to rework the sound in that way before blending in your overheads to add back a sense of ‘a kit in a room’, or to start with your overhead image and then shape the close mics (or use them as triggers) to reinforce that overhead image, smart:gate can be a very effective tool. Also, it’s a fairly painless process: though there’s scope for tweaking, I found that the initial AI‑suggested configuration was generally pretty close to what I wanted.

It’s worth me stressing that smart:gate is still operating as a gate, by which I mean it’s not performing any sort of ‘unmixing’ process to do it’s thing. This means your audio is left intact, without any nasty artefacts, but in gating your kick, if your snare plays at different times to the kick then it will easily be kept out by smart:gate’s content aware processing — it will identify only the kick hits and not the snares — but if a snare hit coincides with a kick hit, as the gate opens for the kick it will also allow the snare to bleed through.

I’ve talked a lot about drums because it’s such a common application for gates, but they can be used on other sources too, and one application I explored during the review period was cleaning up vocal recordings — trying to remove backing track bleed from headphones. With the same qualifier that I noted just above, smart:gate did very will indeed at this job.

A final thing to point out is that smart:gate’s smart gating comes at the cost of a little processing latency. So while it works very well as a mixing or pre‑mix prep process, it’s not really appropriate for use in live sound applications.

...the ‘smart’ label is definitely justified, as it enables you to approach the task of gating in a way that you just couldn’t with a conventional gate.

Get Smart?

I find Sonible’s smart plug‑in range very impressive generally, and smart:gate is no exception — the ‘smart’ label is definitely justified, as it enables you to approach the task of gating in a way that you just couldn’t with a conventional gate. Importantly, it can be very easy to use: pick the appropriate target source, let the plug‑in analyse the incoming audio and it’s a case of ‘hey presto! Job done!’ But I love that you can then dig into the details should you feel the need.

So, if your music production work regularly involves using noise gates — the most obvious scenarios are with multi‑channel drum recordings or full band tracking sessions – then smart:gate could make it much quicker and easier for you to clean up unwanted bleed captured on different mics, and in a commercial setting where time means money there’s a lot to be said for that. Helpfully, there’s a fully functional 30‑day free trial, and it’s well worth downloading.