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Q. Should drum close mics be gated?

By Mike Senior

When using noise gates to tackle spill on drum mics, it’s usually a good idea not to remove the spill altogether — be sure to use any ‘range’ or ‘floor’ control so that there’s a limit to how much attenuation is applied when the gate is closed (as indicated here by the yellow line on the meter of Pro Tools’ bundled Expander/Gate plug–in).When using noise gates to tackle spill on drum mics, it’s usually a good idea not to remove the spill altogether — be sure to use any ‘range’ or ‘floor’ control so that there’s a limit to how much attenuation is applied when the gate is closed (as indicated here by the yellow line on the meter of Pro Tools’ bundled Expander/Gate plug–in).

For Christmas, I treated myself to some pro–studio time to record real live drums. I’m now mixing the recordings at home and I would appreciate some help. When I play all the mics flat (all open) the sound is very good, if a bit too ‘alive’ or distant. So I’ve done the ‘proper job’ and gated the individual mics making sure that only the hits come through, not the spill — although obviously, I don’t touch the ‘ambient’ mics. The issue is that now the drums sound thin and unexciting in comparison. What’s the ‘secret’? Shall I not bother with gating them, especially the three dedicated tom mics? I worry about the potential phase mess.

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Mike Senior replies: The problems you’re encountering are by no means unusual amongst small–studio engineers, so take heart! The first thing to do is ditch the preconception that the only proper way to mix drums is to gate all the close mics. As you’ve discovered, all the spill that you gate out in this way is actually an important part of what makes the drums sound good! Seeing that you recorded professionally, I’d expect the spill contributions of each mic to have been fairly carefully considered, so the best way to deal with mixing such a recording is simply to try balancing it first — and only reach for gating when there’s a specific problem you want to solve.

It sounds to me as if your primary concern is that the raw balance feels too ambient overall. Now, I’m assuming you’ve already tried turning down the level of any overheads and/or room mics in the balance, but have discovered that you also lose the sense of size, width, and harmonic complexity into the bargain. This is entirely to be expected, because those mics not only catch more room ambience, but they also capture a much more natural–sounding timbre for the instrument than close mics typically do. In other words, if you turn down the ambience, you also turn down the realism.

Fortunately, there are plenty of solutions. The easiest would be to insert something like SPL’s Transient Designer onto the drum bus and turn down the Sustain control a little — this can be tremendously effective at reducing the apparent reverb tail. If this isn’t doing what you need, you need more instrument–specific control, and triggering limited–range gates on the overhead/room mics is a more flexible alternative. For example, if it’s mostly the snare sound that loses out if you turn the room mics down, here’s what you’d do:

  • Bring up the room mic(s) to the point where you like the snare’s timbre, ignoring for the moment the fact that the drums mix will now seem too ambient.
  • On the room mic(s), insert a gate plug–in that can accept an external side–chain.
  • Send the close–mic snare signal to the side–chain of that gate using your DAW software’s routing facilities.
  • Set the gate’s attack time fast, and tweak the threshold control (and if necessary the side–chain filter settings) so that the gating triggers reliably on each snare hit. The goal is to get the gate opening whenever a snare hit comes along, releasing a burst of the room–mic signal.
  • Now adjust the gate’s range control to reinstate the desired level of room–mic signal between the snare hits (less than 6dB of gating can often be enough) and adjust its release control to achieve the desired snare ‘tail’ from the room mics.

Most modern DAWs should provide the facilities for side–chain triggering a gate, but if you don’t have a gate with a range control, you can achieve a very similar effect by duplicating the room–mic channel, hard–gating the duplicate, and then mixing the gated signal with the ungated signal.

Finally, you mention a fear of ‘phase mess’ as a reason for gating the close mics. Again, I don’t think this is actually a decent reason for gating. Save it for when you’ve got too much spill on some mic or other, or where that spill sounds horrible (where hi–hat spill is being mangled by the off–axis frequency response of a cardioid snare mic, say, or where strong sympathetic resonances on the toms are muddying the kit tone as a whole). If you’ve recorded professionally, hopefully there should be little need for that kind of trouble–shooting. Besides, it’s not difficult to avoid phase problems — just flip the polarity switch of each new mic you add in as you build up the kit sound and choose the setting that sounds best!

Published April 2016