Engineers have been gating drums since the Kepex was introduced by Allison Research in 1970, and apart from the 1982 Drawmer DS201 adding useful key filters, not much new has happened in the world of noise gating, apart from the ‘look ahead’ function afforded by digital plug-ins. But Sonnox’s Oxford Drum Gate has been developed with clever new functions targeted towards engineers mixing drums where there is unwanted spill.
The plug-in window is huge (you can re-size it to even more huge) and looks modern, clear and sophisticated. There are three main tabs: Detection, Decay and Leveller. On the Detection page, a vertical slider sets the Open Threshold. As you pass audio, the Detect Transients graph shows either 1, 2 or 4 bars of audio before scrolling onto a fresh page, or you can also set a continuous scroll displaying from 2 to 8 seconds. The graph indicates the transients detected and how they correspond with the Threshold. Different colours are used on different hits’ audio waveform to indicate whether they are considered valid triggers or not.
To the right is a Match Transients section, where you can select Kick, Snare or Tom algorithms and the plug-in will try and determine whether each hit is likely to match the drum in question. This uses a machine learning algorithm to differentiate. A separate Threshold slider allows you to determine this effect. This section is particularly useful for letting through those “ghost notes”, even if there is quite a lot of spill from another drum.
Furthermore, you can also “teach” the Oxford Drum Gate what your particular drum sounds like. There’s a Learn Unmatched function; simply click the button and play the hit that should (but didn’t) open the gate, and it will register that sound’s fingerprint and learn to open when it next passes over that – or similar hits. Conversely, there is a similar Remove Matched function to “unlearn” hits that are opening the gate when you don’t want it to. If you find you are getting double-triggers appearing or some transients are not detected, there is a hidden Transient Settings section where you can adjust the Sensitivity, and you can also engage and roll up a Sidechain Filter with continuous settings from 20Hz to 1.5kHz, taking any low frequency rumblings out of the equation.
So, now we’ve got it opening as desired, we move onto the Decay tab which displays a very cool looking spectrogram-style waveform graph. A main slider on the left sets the decay time, but superimposed on the graph are three adjustable nodes to let you centre in on the resonant frequency of the drum. This allows you to increase the decay for the “body” frequencies of the hit, whilst chopping off the extraneous signal more briskly. Cut-offs either side narrow in on the frequency, which is usually pretty easy to see on the graph, then you can pull up the Resonant Decay node to increase decay of that portion of the frequency range – great for some tom-tom boom.
On the right is another fader Shorten Decay (on softer hits) which helpfully enables you to tighten up the release for ghost notes, which are usually shorter. The Gain Reduction slider is simply what is traditionally called the range on a gate; defaulting to 40.0dB you can slide it up to zero or down to -80.0dB.
But we’re still not done, as there is another very clever trick on the third tab, Leveller. Here you can set a vertical Split fader on the left to set a point where hits will be determined as either Loud or Soft, with horizontal guiding lines crossing a similar audio graph to that on the Detection page. Having determined a split point, a separately variable amount of levelling can be introduced to Loud and Soft hits in order to even things out for more consistency. You can even set the Leveller automatically by playing in a short section. If your drummer doesn’t whack the drums consistently (when you want them to), this is invaluable. And if you want to bring up the playful Mitch Mitchell ghost snare rolls in a busy mix, this gives you unprecedented control.
On the far right are Bypass, level Trim, and there is a MIDI function. The “live” MIDI output seemed a little unreliable, with oddly varying note lengths and missing hits, but by using Capture followed by Drag-and-drop, hits were consistent and lined up precisely. However, there is no offline function as with, say Massey DRT.
A pop-out Context Help section explains functions at the bottom and the window automatically re-sizes accordingly.
Presently, there is nothing that comes anywhere close to the functionality of the Sonnox Oxford Drum Gate. The machine-learning functions are terrific, and the human learning required to set it up successfully is thankfully minimal. Even though there are – necessarily – quite a few settings to play with, there is clearly a lot more going on “under the bonnet” to make it work so well, and it’s way quicker and easier than manually muting between hits.
Pros: Supreme gating for otherwise unachievable automated function, Leveller gives unparalleled control over consistency.
Cons: Fairly high latency, real-time MIDI output unreliable, no offline MIDI capture.