Production Techniques: ‘Gated Reverb’

The iconic drum sound of the 80’s and one that has recently been returning to popular music 30’s years later, is created using a technique called ‘gated reverb’. This is that full, punchy sound primarily applied to snare, kick and toms familiar in the music of Prince, Duran Duran, Peter Gabriel, Phil Collins and Bruce Springsteen. Throughout the 80’s it was a drum sound virtually inescapable in popular music, whereas before its discovery in 1979, drums had traditionally had a very ‘dry’ sound. A quintessential example of gated reverb can be heard below with John Mellencamp’s ‘Jack and Diane’. Fast forward to 2:30m where you can clearly hear the effect in the snare and toms:

So what exactly is gated reverb? This effect is created using two key elements:

  1. A Large Reverb &
  2. A Noise Gate

Reverb

We experience reverb everywhere in our daily lives, so much so that we rarely notice it. It helps us determine what direction a sound is coming from and how far away it is. Originally, reverb in recording was created using the natural sound of the space where recording was taking place, like a church, echo chamber or concrete car park. The sound source was placed in one area of the space and a microphone at another. The microphone would collect the direct sound from the source, but would also feature the ‘reflections‘ of that sound bouncing off the walls and other surfaces in the space.

reverb_chart_1200x627-1
Reverb Chart

It was not practical for recordings to always take place in spaces that would produce the reverb sought, so ‘Plate Reverb‘ was developed. This was the first artificial reverb device developed and worked by sending a sound into a box containing a large sheet of

plate reverb
Early plate reverb unit

aluminum. The signal would travel around this metal sheet and out the other side after it had collected some of that reverberation. Once again, the practicality of this method was not ideal as these units weighed as much as 300kg! This led to the first digital reverb unit in 1982, the ‘AMS RMX16′. It had (in a compact and light unit), presets generated by complex algorithms emulating spaces like churches, concert halls and echo chambers. This was a game changer for engineers who were now able to apply reverb affects to sounds quickly and at the press of a few buttons.

Noise Gate

The sound of reverberation alone however does not give us the powerful punchy drum sound that typified the 80’s; it requires the addition of a noise gate. A noise gate is a device that can cut a sound signal when it is not playing (or softer), but let it through when it is playing again at a certain amplitude. This gate works with the reverb by not allowing the reflections to decay naturally, but cutting them off at a point determined by the amplitude threshold (set by the user ). This allows the power of a large reverb sound to still be employed without the tail or decay interfering with the next drum strike or spoiling the clarity and detail of other elements in the mix. Now Berklee Professor and producer Susan Rogers (most famous for her work with Prince in the 80’s), describes it thus: “Picture it like a tidal wave, a huge wave suddenly stopping and hitting a brick wall. That, is gated reverb” (Earworm S1 – E2, 2017)

There are five main settings on a noise gate (outboard unit or plug in). They are:

  1. Threshold: This setting determines the amplitude level at which the gate will allow the sound through
  2. Attack: This is used to set the amount of time it takes (in milliseconds), for the gate  to open and allow sounds through when it has been closed.
  3. Hold: How long the gate will stay open after the sounds amplitude level has fallen below the predetermined threshold.
  4. Ratio: The level of ‘wet’ or gated sound vs the unaffected signal (allows blending), &
  5. Release: Determines how long (in milliseconds) it will take for the open gate to close and cut the reverb’s decay.
Pro-Tools-Noise-Gate
The ‘gate’ plug in I have been experimenting with in Avids Pro Tools DAW

Methodology

The basic process for creating gated reverb in any Digital Audio Workstation is as follows:

  • Send the original signal to an auxiliary channel It is important here to ensure this send is a ‘post fader send‘, which means that if we adjust the fader, the ‘Wet/dry’ reverb signal can be controlled
  • Insert a reverb plug in onto this auxiliary channel that is now receiving the original signal and choose something large from the suggested presets (have some fun with just how big)! Compression can now be used if desired to fatten up the reverb sound before deploying the gate.
  • Now using a separate bus send, route the original signal again to the auxiliary channel initially created for the reverb and add a gate plug in (like the Dyn 3 pictured above), below the reverb plug in already present. Ensure that this send is ‘pre fader’ however, as we do not want an adjustment in the original signals fader to interfere with how the gate reacts when cutting in and out. This send will also be a keyed send to the gate plug ins sidechain and its signal will be used to trigger the gate more accurately.
  • The final stages are to experiment with the wet and dry level of the reverb and the threshold, attack, hold, ratio and release of the gated signal and these settings will depend on the sound you are seeking and indeed the style of music you are mixing. For a more detailed look at how to create gated reverb see the short video below:

Conclusion

Much like the Glyn Johns drum mic method discussed in my last production technique blog, the discovery of gated reverb was a fortuitous accident when Phil Collins and Peter Gabriel were recording drums for Gabriel’s third album ‘Intruder’. You can read an interview with the revered engineer involved in this discovery Hugh Padgham and also how he used the technique to record the iconic gated reverb drum sound on ‘In the Air Tonight‘ by Phil Collins a few years later here. Both reverb and gating are important audio effects and play a crucial role in how the techniques that can augment the music we produce have evolved throughout the history of recorded sound. When combined, they create that full, punchy, ‘whip cracking’ drum sound so popular in the 80’s and which is experiencing a revival in much of the popular tunes of today.

References

Featured Image courtesy of http://www.sonicvistastudios.com/news Retrieved 27/11/17

Reverb Chart courtesy of https://blog.landr.com/5-simple-reverb-techniques/ Retrieved on 27/11/17

Early Plate Reverb unit picture courtesy of https://theproaudiofiles.com/plate-reverb/ Retrieved on 27/11/17

Susan Rogers quote courtesy of https://www.youtube.com/watch?v=Bxz6jShW-3E Retrieved 27/11/17

 

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