Logic Pro: Gating Toms

Screen 1: With so many versions (saved as Track Alternatives) of this drum performance to choose from, using the Remove Silence function would be a major time commitment.

Tidy up your tom hits with this ingenious gating trick!

As I’ve previously discussed in this column, mixing live drums presents an array of challenges that, fortunately, Logic Pro is well equipped to help us overcome. Today I want to talk specifically about the toms. In most drum recording situations, the bleed from the snare and cymbals is so prevalent in the tom’s spot mics that it interferes with the overall balance in an undesired way.

Think about it: you’ve worked diligently to get your kick and snare sounding perfect, you bring in the overheads and the overall picture begins to emerge. Now you start fading in the tom tracks and the entire sound and image of the drum kit are changed. It sounds as if you’ve added four badly placed room mics to the mix. Cleaning up the tom tracks is essential in most styles of music.

When I’m mixing for a client, the tom tracks usually arrive with a fair amount of cleaning done already. In the cases where they don’t, I turn to the Remove Silence function in Logic Pro. Simply pressing Control+X is a robust, simple and intuitive method of removing the dead space around the tom hits.

When I’m working on my own music, however, Remove Silence is not the option I choose. Why not? For one, I usually have several drum takes organised with Track Alternatives to choose from. Also, the drummer may decide to do another run at the song and send me new files at any point in time. Additionally, I may not yet have comped together my final performance. Because my drum tracks are in such a state of flux, Remove Silence isn’t the best option. It should also be noted that especially loud snare bleed in a tom mic would still result in a less than ideal render.

The challenge for me was to figure out an automated process that would remove the bleed between the tom hits, and which could stay in place while I switch between different drum takes. The solution that I came up with, at the risk of sounding immodest, is clever, elegant, functional and original.

Have Your Gate & Eat It

You’ve all heard the paradoxical dilemma of wanting to have your cake and eat it too. I always thought there was an easy solution: get two cakes. Eat one, and keep one. Done. So why not use this approach to our gating dilemma?

If we use the Noise Gate plug‑in, we are able to dial in a setting that eliminates the snare and preserves the tom fill. But the threshold setting leaves very little margin for error.

Let’s take a look at an example. In Screen 2 we have a rack tom track with a tremendous amount of snare bleed. If we use the Noise Gate plug‑in, we are able to dial in a setting that eliminates the snare and preserves the tom fill. But the threshold setting leaves very little margin for error. It may work for this particular passage, but if the snare is hit any harder, or the tom is hit any lighter, we will have created more problems than we solve.

Screen 2: The first six hits you see in this tom track are from snare bleed. Although I can set the gate to close on the snare and open on the tom, the margin of error is so small (1dB) that this setting would probably not work throughout the whole song.

What we need to do is find a way to make the snare hits softer in the tom track so that there’s more disparity between the two drums. Then, our noise gate can more accurately — and with more flexibility — open only on the tom hits.

The way I’ve devised to achieve this is by using the ‘two cakes’ concept. That’s right, we’re going to add another gate before our gate. But this noise gate is going to play a different role. This ‘pre‑gate’ is going to use the snare track’s own signal to gate snare spill out of the tom track.

When I was originally conceiving this concept, my first thought was to use the Compressor plug‑in on the toms, with the snare routed to the side‑chain input. This would set up a form of ‘ducking’, a technique that has its origins in broadcasting. Suppose you were in a live scenario playing music and you needed an intermittent voiceover. You could, of course, manually lower the music’s volume when you needed to speak, but that could be exhausting and unreliable. By placing a compressor on the music track with gain reduction keyed from the voiceover, the music is usefully attenuated only when the VO is occurring.

So why not employ the Compressor plug‑in in this situation? Well, I intended to, but I inadvertently opened another Noise Gate plug‑in. In the moment before exchanging the effect, something caught my eye. In the left panel of the plug‑in’s interface there are buttons to turn the plug‑in from Gate mode to Ducker mode. That’s convenient.

Screen 3: My final dual‑gate setup. The top gate is set to Ducker mode, with its side‑chain input being fed from the snare track. This reduces the level of snare bleed sufficiently that the second gate eliminates everything but the toms.

This is a good time to point out that most of the dynamics processors in Logic Pro (and any DAW or hardware) really do one thing: adjust the volume. The Compressor, Limiter, Expander, Enveloper, and Noise Gate are essentially automated volume knobs with a bunch of parameters that determine, amongst other things, how much to turn a track up or down by, for how long, how quickly, and so on.

We tend to think of a gate as a binary open or closed process, but it’s really more of a super‑fast expander. And in Ducker mode, it’s more of a super‑fast compressor.

Back to our example, we need to set the side‑chain input of the ducker to the snare track. (The list of side‑chain sources can get out of hand on larger projects, and the sequential ordering can make finding your snare track a real time‑suck. A little trick is to select the track you want in the side‑chain, and, with the Inspector open, peek into the track parameters and make a note of the channel number. Now you can find the track in the list with ease!)

With the snare drum now set up to duck itself out of the tom track, we are ready to go. Set the attack time to the lowest value. If you solo the tom track (you should keep the second gate disabled until you tweak the settings on the ducker) you will now hear that the snare hits are virtually gone.

If you can still hear a little blip of the snare, that’s likely because the attack time isn’t quite fast enough to catch the transient. No worries: slide the lookahead parameter to a few milliseconds and it should eliminate the small click. (Actually, you don’t even need to use lookahead. Remember, we aren’t necessarily trying to eliminate the snare from the tom track completely, we just want its volume to be different enough from that of the tom for our second gate to do its job.)

Gate Expectations

Now, when we enable the second Noise Gate plug‑in following the first one, it’s very simple to dial in a setting that completely removes everything but the tom hits. Because the snare is so low in level (after the ducker), the second gate has a wider margin of error to work with.

I would be remiss if I didn’t point out one very serious caveat of this technique. Can you guess what it is? What happens when the snare is hit at the same exact time as the tom? Unfortunately, you will lose the tom hit. When this happens, you should automate the ducker to do nothing on that particular section.

Does this occur often? Not in every drum performance, but certainly in enough of them to pay attention. So, like with any automated process, best practice would be to carefully listen to each track before any final mixing.

So now the only thing that’s left for discussion is what we’re going to call this technique. Maybe the Ricard‑O‑Gate? How about the SOS Bleed Blaster? I think I’m OK with Duck‑n‑Gate. What do you think?