Sonnox Oxford Drum Gate 2

The Detect page will look familiar to existing users of Drum Gate — but its Classify view now gives an assessment of the algorithm’s confidence that it has correctly identified each hit.

Already much more than a simple gate, the Oxford Drum Gate is back — with significant enhancements!

When Sonnox first released Oxford Drum Gate, I wasn’t initially inspired by the idea of another noise gate, but it soon became clear that this was something different. By identifying different drum hits, regardless of their level, it solved a problem I encountered on almost every mix session simply and efficiently. Oxford Drum Gate 2 builds on that original version, adding a number of useful features that broaden what can be achieved and can make it much more useful in complex sessions. Happily, though, Sonnox haven’t sacrificed the clarity and efficiency that made it so effective. Neil Rogers reviewed version 1 in SOS March 2020, and covered the core concepts very well, so in this review I’ll focus mostly on the new features.

In Alignment

The new Align page works across multiple instances, bringing all the sources together into a single pane. In most cases, the plug‑in uses the DAW’s track names to group related channels and determine the detection type automatically. After a short audio capture, the polarity, timing (delay) and phase rotation can be optimised for all tracks simultaneously. You might think an ARA plug‑in would have been best suited to alignment tasks, but it’s arguably less appropriate for gating and levelling, so Sonnox opted for real‑time processing. An alignment‑only mode is provided, though, for situations where phase optimisation is desirable but gating generally isn’t (for example, on ride cymbal tracks).

Once the capture has been performed, the results are displayed in a list view and can be auditioned directly. Optimising the phase relationship between mics will often deliver a tighter, more focused sound. Still, it isn’t unusual to find that the original recording feels more natural, so being able to check the result quickly is important. One detail that I particularly like, therefore, is the momentary bypass switch; this makes it incredibly quick and easy to compare the aligned and unaligned versions. You can also try running the alignment process more than once — it can produce slightly different results each time, since there are usually multiple possible solutions and several different settings may give equally good correlation.

Drum Gate 2 introduces the ability to automatically optimise polarity, delay and phase rotation of multiple drum mic channels.

The Detectorist

The Detect page is similar to version 1’s Detection page, but most work will likely be done in the new Classify view. The scrolling, rectified waveform display is similar to that shown in Detect, but the threshold control no longer represents level. Instead, it shows the degree of confidence the detection engine has that each hit matches the selected drum type. This is an important distinction, because once the source input has been set, normally to Input (External, MIDI and Alignment‑only options are now available) and the drum type has been chosen from the menu, the gate isn’t responding to amplitude, but rather to the tonal similarity of each hit to the selected drum type. It’s this that makes it possible to isolate lighter hits such as ghost notes that sit below spill from other kit pieces. (Anyone who has tried to gate a busy snare part using a level‑based threshold will know just how quickly that can become impractical!)

Snare spill is inevitable on hats of course, but Drum Gate 2 proved far better at addressing this than a conventional gate.

The Add and Remove functions from the original version are still available if further refinement is needed. In practice, though, the more intelligent detection sometimes encourages slightly different approaches. When gating toms, for example, I found that spill between neighbouring drums could trigger the detector because of the similarity in tone. Rather than fighting this on individual tracks, it was quicker to route the toms to a subgroup and apply Drum Gate there. The new hi‑hat option works well, though I had to look hard for a session with a hi‑hat track, as I don’t usually close‑mic hats. Snare spill is inevitable on hats of course, but Drum Gate 2 proved far better at addressing this than a conventional gate.

Adaptive Decay

The Decay page remains largely unchanged from the original version, and remains one of Drum Gate’s most powerful features. As before, it allows a global release time to be set, while also making it possible to extend the decay only within a chosen frequency range. This makes it easy to bracket the resonant band of a tom and allow that part of the sound to ring on while keeping the decay short elsewhere.

An adaptive decay facility can reduce higher‑frequency bleed while allowing the wanted drum’s decay to ring out naturally.

The new Adaptive mode introduces an HF Damping control. This applies dynamic high‑frequency reduction to the hit’s decay, and is particularly useful for controlling cymbal bleed on tom mics, as it preserves the brightness of the initial transient and then allows the natural low‑frequency decay of the wanted drum to remain, while excluding high‑frequency spill in the tail. I found that it could draw attention to itself if used too aggressively, but when applied more moderately it’s a very practical tool; I didn’t usually need to use more than the lower part of the HF Damping control’s range.

Level & Clip

Version 1 of Drum Gate included a hit‑based drum leveller, which allows the level of each whole hit to be adjusted clip‑gain style, without the timbral side‑effects that conventional compression or limiting can introduce. This feature remains unchanged in Drum Gate 2, but a Hit Clip function has been added. Clipping has become a popular alternative to limiting in drum production, as it allows more aggressive peak control without the pumping or tonal change that limiters can produce. But here, as with the drum levelling function, a consistent amount of clipping can be applied to each, regardless of its level. You just dial in a specified amount of clipping in decibels, and it will be applied to every detected hit. There’s an Auto Gain control, and the display shows the effect of the current settings, with a shaded halo extending below the dashed target line indicating how much clipping will be applied, but it’s important to note that this does not represent a conventional ‘ceiling’.

You can now clip all hits by the same amount, regardless of their level, for tonal consistency, but you also have a split option to treat quieter hits differently from louder ones.

Of course, this kind of level‑independent processing has the potential to affect quieter notes in undesirable ways. To counter that, Drum Gate 2 lets the user treat loud and soft hits differently — you define the threshold that determines which hits are loud or soft. It allows, for example, strong snare hits to be clipped while leaving ghost notes untouched, and generally makes the feature far more useful. In one mix session, the snare track contained a mixture of side‑stick and full hits, and the split control made it easy to apply clipping only to the full hits without affecting the side‑stick.

Conclusions

Drum Gate 2 strikes a very effective balance between utility and feature creep — it provides a great deal more control, but does so without cluttering the interface or disrupting the clear, fast workflow of version 1, even when using several instances across a full drum kit. Just as importantly, it sounds excellent. Anyone who spends time mixing live drums will recognise that moment when bypassing gates, compressors or limiters suddenly makes the kit feel more open, revealing that you’ve taken the processing too far. That’s happened far less often for me with Drum Gate 2. Because it detects hits rather than tracking the instantaneous level, and because so much of the processing is frequency‑ and event‑aware, it tends to preserve the natural character of the recording, even when doing quite heavy work.

For many mixing situations, it could easily handle everything from clean‑up to level control to alignment without the need for additional processors.

Of the new features, the HF Damping control in the Decay page proved particularly useful for cleaning up tom and snare tracks without losing the body of the drum, while the refinements to the detection system make it easier to isolate the desired hits without endless adjustment. The expanded source options are also welcome, especially the ability to use external side‑chains or MIDI when needed, which makes the plug‑in suitable not only for straightforward gating but also for sample augmentation and more complex workflows. For many mixing situations, it could easily handle everything from clean‑up to level control to alignment without the need for additional processors.