Why Your Kick and Snare Deserve Their Own Parallel Compression Bus

The short answer

Most engineers send the whole kit to a single parallel compression bus, which forces a compromise: pushing that fader for kick and snare attack also drags up the toms, overheads and room mics, and the kit stops sounding like a kit. The fix is two parallel busses. Route kick and snare to a dedicated crush bus, route the rest of the kit to a separate drum crush, and fold everything into one all drums bus at the end. You get the attack without the collateral damage.

The problem nobody names out loud

Parallel compression on drums is close to universal advice, and it works. Send the kit to an aux, obliterate it with a compressor, blend it under the dry signal, and the drums get weight and density without losing transients. Fine. Classic. Correct.

Here is what actually happens six hours into a mix.

The arrangement gets dense. Guitars are stacked, keys came in, the vocal is up. And the kick starts disappearing. So you reach for the parallel bus fader, because that is where the attack lives, and you push it.

The kick comes forward. Good.

The overheads also come forward. The toms come forward. The room mics come forward. The whole kit inflates like a balloon, the cymbals get washy and forward, and the thing that was a drum kit is now a compressed smear that happens to contain a drum kit. So you pull it back, and you lose the kick again.

You are not doing anything wrong. You are using one control to solve two different problems.

Chris Shaw hit this wall years ago and did the sensible thing: he stopped negotiating and split the bus.

The routing, exactly

Here is the structure. It looks like more work than it is. Build it once in your mix template and it costs you nothing forever after.

Step 1. Sub the kick and snare separately. Real drum recordings arrive with two kick mics plus a sample, and two or three snare mics. All the kick mics go to a kick sub. All the snare mics go to a snare sub. This alone is worth doing, because now "more kick" is one fader, not four.

Step 2. Combine into a kick and snare sub. Both subs feed a single kick and snare bus. This is your dry, front of the kit signal.

Step 3. Build the crush bus. Sends from the kick sub and the snare sub feed a dedicated parallel bus. On it, a dbx 160, and here is the part people find annoying: Chris leaves it on the default setting. It works. It sounds great. Not everything needs to be interrogated.

Step 4. The rest of the kit gets its own path. Toms, hi hat, overheads, rooms go to a drums bus, and out to their own drum crush bus with a Smack compressor on it. Separate territory, separate control.

Step 5. Everything folds into one all drums bus. The kick and snare sub, the kick and snare crush, the drums bus and the drum crush all arrive at a single all drums destination. On it, a Kush compressor at the ready for glue over the top of everything, plus a Blue Cat Patchwork instance, which is really a wrapper that adds a mix knob to any plugin you put inside it. Sitting there fully dry. So when the artist says "what if the drums flanged in the bridge," you drop a flanger in the wrapper, ride the mix knob to 100% for four bars and back. Thirty seconds, not thirty minutes.

How to actually use it

This is where the split pays off, and the technique is almost embarrassingly simple.

Start with the crush bus all the way down. Not low. Down. Then leave it there for as long as you possibly can.

Build the mix. Get the balance. Bring in the guitars, the keys, the vocal. Let the arrangement fill in. At some point, usually well into it, you will notice the kick has lost its front edge, or the snare has stopped cutting.

That is the moment. Push the crush fader.

Because it only contains kick and snare, you get attack, weight and density delivered exactly where the problem is. The overheads do not move. The rooms do not move. The kit keeps its shape and its air, and the front of it comes forward on its own.

Chris describes the result as the kick and snare just banging, and yes, that is a technical term now.

Why this works, in one paragraph

Parallel compression brings up low level information. On a kick and snare, low level information is body, sustain and the tail of the transient, which is exactly what you want more of. On overheads and room mics, low level information is bleed, cymbal decay and the sound of the room, which is exactly what you want less of when a mix gets busy. One bus applies the same medicine to both patients. Two busses lets you dose them separately.

Common mistakes

• Sending the parallel bus from the drum bus output instead of using sends. You lose independent control. Use sends from the kick and snare subs.
• Riding the crush fader early. If it is up at balance stage you will build the whole mix on top of a crutch, and by the time the mix is dense you have nowhere left to go.
• Over compressing the crush bus and under blending it. You are meant to slam it. It is supposed to sound bad soloed. Judge it only in the blend.
• Forgetting to check mono. Parallel busses can build up phase problems fast, especially with multiple kick and snare mics arriving from different distances. Check early, not at the end.
• Building this from scratch on every session. It should live in your template. Set it up once, spend your future sessions using it rather than wiring it.

The bigger principle

The interesting thing here is not the dbx 160 or the Smack. It is the diagnosis.

Chris did not discover a new plugin. He noticed that one fader was being asked to solve two unrelated problems, and he built a second fader. That is most of what advanced mixing actually is: recognising when your routing is forcing you into a compromise, and refusing to accept the compromise.

Any time you find yourself pushing a control and thinking "yes, but," that is a routing problem wearing a plugin costume.

FAQ

How much parallel compression should I use on drums? There is no target amount. Set the compressor to work hard, start with the return fader down, and raise it only when the mix demands more attack. If it is up before the arrangement is full, it is up too early.

What compressor is best for a parallel drum bus? A fast, characterful compressor. A dbx 160 style unit on kick and snare and something more aggressive like Smack on the rest of the kit works well. The choice matters far less than the routing.

Should the parallel bus be pre or post fader? Post fader, so the parallel signal follows your balance moves. Pre fader means every level change breaks the relationship you set up.

Do I need two parallel busses on a simple three mic kit? Probably not. The split solves a problem created by many mics and lots of bleed. On a minimal kit, one bus is fine.

Does this work outside Pro Tools? Yes. The routing is DAW agnostic. Subgroups, sends and busses exist everywhere.

Keep going

• Watch the full series: Chris Shaw: The Mix Template on Puremix
• Related: What Actually Goes in a Pro Tools Mix Template
• Related: Three Compressors at 40 Percent
• Get the full library: Puremix Pro