When working with recorded multitrack drums, you will almost certainly encounter drum spill. Also known as bleed, spill in drum recordings is sound of other drums bleeding through to nearby microphones. For instance, spill can be the sound from the kick drum sound being also picked up by the snare mic.

Opinions are usually divided on what to do about bleed or spill. Some choose to embrace it as they favour the sound of off-axis sound blended in with spot and ambient microphones. Others, prefer a more clinical approach reducing or even removing bleed altogether of bleed because they find spill limits their choices in a mix. To get started we recommend that you listen to our Podcast episode in which we discuss our opinions on the topic of bleed.

In reality, there's no right or wrong with spill or bleed, after all, shouldn't we be making informed decisions on spill based on the job in front of us? If you feel bleed is causing you issues, remove it. If you like the sound of it, use it!

Artistic choices aside, bleed can throw up a challenge or two. Hi-hats can sound too prominent or shrill down a snare drum mic. This, of course, can depend on how the drummer played and how the kit was mic’d. You could also come across a drum mix in which you feel the cymbals need backing off in a tom mic. Whatever your reasons, bleed, if you choose to embrace it, eradicate it or treat it slightly is an important choice and decision we all make when approaching a drum mix.

There are several methods you can apply if you need to treat bleed in a multitrack drum performance using stock plug-ins in your DAW of choice. While many of these are effective, you may find some of these techniques are not refined enough for your needs. Luckily, there are several third-party plug-ins explicitly designed for processing drum bleed. We'll take a look at those later. First, let's learn a handful of methods you can try now, for free, using your DAW with either some third-party plug-ins you already own or stock plug-ins that came with your DAW.

Editing Drum Bleed Manually On The Timeline

Drum bleed doesn’t necessarily need addressing with a plug-in. You can easily strip away audio between direct drum hits using facilities such as Strip Silence in Pro Tools, or by using basic audio editing tools right on the timeline. This approach is favourable with engineers who like to treat bleed on tom channels. Toms are not typically hit as often as other kit pieces, making them easier to tackle on the timeline. Bleed from other sources, such as snares and cymbals, captured down tom microphones can be easily removed using manual editing, thus addressing bleed. For approaching bleed in other kit pieces, manual editing is a painstaking and time-consuming process.

Warning, working through prominent kit pieces such as kicks and snare this way is a process that can be all too easy to get lost in. The results may also turn out to sound very choppy with the decays sounding unnatural. As we stated moments ago, the manual approach is a quick and easy way to remove bleed in tom channels, only if the toms are not a massive feature in the drummer's performance. Read on to learn more focused ways of addressing bleed.

EQ Drum Bleed With Targeted Cuts

Never underestimate the power of EQ if bleed causes you trouble in drum mixes. Sure, EQ may not be the sexy golden bullet plug-in for removing bleed, but it is convenient if the adjustments you need to make to your spill concerns are small.

Say the fundamental of the kick drum is protruding a little too much in the snare bottom channel. An easy remedy to this is to establish the kick frequency in an EQ inserted on the snare bottom mic cutting it enough to reduce the weight of the bleed. Maybe the spill of the cymbals are too bright in the toms? Again, simple enough to dull down using low pass filters on tom channels. A low pass filter, if set carefully, should leave the tone of the toms relatively untouched while attenuating the excess cymbal spill.

Noise Gate To Lesson The Level Of Drum Bleed

A noise gate opens or closes to let sound in or out. In the case of reducing bleed we use noise gates to keep spill out, letting direct sound that we want to hear through. Direct sound, being the snare sound from a snare top mic will be the loudness most prominent part of the signal with bleed from surrounding kit pieces being significantly lower. With this level difference, we can use the threshold in a gate set below where the snare level is louder than the bleed to close the gate to either reduce spill or, if the performance allows, cut it significantly.

Notice we did not say cut altogether. There good reason for this. If you set out to reduce bleed completely on direct drum channels often noise gates can turn out to sound choppy. Other times a few false triggers can occur opening the gate when you don’t want it to. A better, more sympathetic way working with gates is to not overdo it. If your gate has ratio and range controls you should experiment with these. Both will keep the gated sound in proportion, allowing some bleed to come through but at a lower level. This approach is expansion. You preserve ghosts notes and other subtleties by retaining some bleed which often gets lost in heavy-handed noise gating.

Some gate/expanders, such as in FabFilter Pro-G, provide side-chain filters. These are very helpful as you can set these to hone the gate's processing within a narrow frequency range. In the case of tom gating, you can tune your gate's side-chain tightly around a tom's fundamental, enabling the gate to open and close with what it hears between those filters.

Use Transient Shapers To Shorten Tonal Sustain Of Drum Channels In Which Bleed Can Reside

Transient shapers, also referred to as transient designers, are a form of dynamics processor. Useful for quickly focusing the sounds of the initial level of impact and sustain length in audio. These often work wonders on percussive sounding tracks helping us to apply just the right amount of size and proportion to drum kit pieces. If bleed is an issue on toms, transient shapers can help focus the direct sound by bringing forward the initial attack hit sound and shortening the length of the natural decay.

This approach may not completely get rid of bleed, especially if you are using a transient shaper that processes full range. Your results may sound too aggressive if overdone but transient shapers are worth a try as they typically have only two main controls. Some transient shapers provide in-depth control, such as Oeksound’s Spiff which examins incoming audio enabling users to apply transient boost or cut processing to parts of the signal that has transient information in. This can be used to quickly hone in on spill which can be reduced fast in impact and sustain.

There are several very capable transient shapers out there. Check out our article below that summarises some of the best on the market today:

Replace Drum Hits With Bleed By Triggering New Samples

Drum replacing, also known as drum augmentation is useful for replacing the sound of specific direct drum kit pieces. If a snare and kick are not quite working for you in a mix these can easily be substituted for different samples altogether that you feel are more fitting. How then can drum replacement help with bleed is it doesn’t reduce bleed?

Consider drum replacement as a form of masking bleed and the direct source sound with new samples. If you feel that the tone of a direct snare drum channel is not salvageable and also features too much audible hi-hat bleed then drum replacement maybe your best bet. Approaching a snare channel such as this you would be killing two birds with one stone as the bleed from the hi-hat will be gone completely. The hats would now be coming through your overhead channels at the very least with the direct snare sound replaced with a more fitting snare sample. Some drum replacement tools also allow parallel processing of samples. With this, you could blend a new snare sample in with the troublesome source snare which would attenuate bleed.

There are several very capable drum replacement tools out there. Check out our article below that summarises some of the best on the market today:

Let’s move onto looking through some third-party plug-ins that have either been designed specifically for reducing bleed in drums or include powerful features that make the process of addressing bleed simple.

Third-party Plug-ins Explicitly Designed To Reduce Or Suppress The Sound Of Bleed On Tracks

Accusonus drumatom2

Fun fact, Drumatom was the first-ever plug-in based on A.I. machine learning algorithms. Developed by Accusonus, Drumatom 2 enables producers to suppress drum bleed in their recordings quickly. Hi-Hat bleed in snare drum tracks is a common spill problem, luckily Drumatom takes this in its stride. It’s super simple to use, and results are super clean with barely any audible artefacts.

You need to import all the drum stems you wish to process into the Drumatom standalone application. The A.I. detects track types while batch analysing for bleed. Focus and fine-tune controls make the process of reducing bleed simple enough that engineers can use to either slightly decrease bleed sounds or remove altogether. Sounds extreme but the algorithm in Drumatom is smart enough to make light work it.

Drumatom is a standalone application. Accusonus also provide an optional Drumatom player. This player inserts like a traditional plug-in within a DAW enabling you to monitor the leakage-suppression in your drum channels within a session listening through plug-ins such as EQ and compression. When you’ve set the desired amount of bleed suppression within the Drumatom standalone app, you simply export your stems and import into your mix.

Watch the Accusonus tutorial video below comparing the results of Drumatom against a handful of traditional processes engineers have used for years to address drum bleed. The results are pretty amazing.

Visit accusonus for more information on Drumatom2.

iZotope RX DeBleed

iZotope introduced the DeBleed module in iZotope RX 6. It’s capable of reducing spill of one track from another track using machine learning technology. This has applications including dealing with reducing or evening eliminating bleed from headphones, click tracks, multiple mic recordings including, addressing drum bleed issues.

What Is Bleed?

Bleed happens when you have a microphone picking up audio that you don’t intend for it to pick up. This presents colouration and separation challenges that result in less control over your mix. Of course, the classic problem is click-track bleed. Even the faintest click track or speaker bleed can ruin your recording.

In this free video tutorial, 'Mr RX It' aka Mike Thornton, is joined by iZotope's Education Director, Jonathan Wyner. Mike shows just how easy it is to remove click track and speaker bleed with the De-bleed module in RX 6 from iZotope.

Using RX Connect, Mike starts by demonstrating how to move audio files from a DAW (in this case, Pro Tools) into the standalone version of RX to take advantage of the program’s full processing power. Then, after processing them, he shows you how to move them back into your DAW.

Even though this video teaches you how to remove the sound of click track bleed from headphones and reducing the unwanted sound from playing a music track through speakers whilst recording a VO, the process of using DeBleed in a drum spill application is exactly the same.

Visit iZotope for more information on RX.

Sonnox Drum Gate

Sonnox’s Oxford Drum Gate is an intelligent gate which understands the difference between a kick drum, a snare and a tom. Instead of just hearing, it actively listens and so can create results which wouldn’t be possible with a conventional, level based process.

As a gate, it goes further than its traditional predecessors. As well as its unique detection features, it offers variable release both across the frequency spectrum and in response to different intensities of hit. It offers a content aware drum leveller which you can use to manipulate the dynamic range of performances without the artefacts introduced by purely level based dynamics processing. It can also be used to capture MIDI from audio recordings for enhancement or replacement with virtual instruments or samples.

Watch our video below which shows you that Drum Gate isn’t purely level based, in spite of the kick drum being far louder in the kick mic than the minimal snare spill (as it should be) if the detection mode is switched to snare, Drum Gate is capable of passing the snare hits and gating out the far louder kick. We also investigate the decay tab where different parts of the frequency spectrum can have different release times and release time can vary between harder and softer hits.

Drum Gate can also be used to detect individual drum hits including kick, snare and toms within mono source recordings (such as ones recorded with ambient microphones). Check out our review to hear Drum Gate in action.

Visit Sonnox for more information about Drum Gate.

SoundRadix DrumLeveler

Drum Leveler isn’t a leveler in the traditional sense but it does level the differences between hits in a percussive performance so the name describes what it does perfectly.

Drum Leveler dynamically changes the gain of hits in a performance, but it differs from a compressor in how it detects the level of the incoming audio. Instead of comparing the instantaneous level of the incoming audio Drum Leveler “understands” drum hits and treats each hit as a discrete event, moving the level of each hit within the threshold towards or away from a target level. This allows Drum Leveler to achieve results simply not possible using a conventional compressor.

To reduce the spill of kick and hi-hat in a snare channel using Drum Leveler you can simply throw an instance of it on the snare. Use the side-chain filter to home in on the snare sound followed by using the target level to decrease the level of bleed in your track.

To learn how to use the controls in Drum Leveler check out the SoundRadix video below.

Visit SoundRadix for more information about Drum Leveler

Wilkinson Audio DeBleeder - $80

DeBleeder is a real-time plug-in by Wilkinson Audio. It’s incredibly simple to use. First, insert an instance of DeBleeder on a track you wish to address the bleed of. The fundamental control then needs to be dialled to the strongest sound in the source track. If this used on a snare channel the fundamental should be easy enough to find. If you experience difficulty finding a fundamental or strong resonance you can make life a little simpler by enabling the audition button to the left of the fundamental dial. The range and reduction dials are the party piece in DeBleed. You will instantly hear a massive reduction in bleed by turning each clockwise that can easily be set to sound natural in your direct channels.

An excellent little addition for Pro Tools HDX users is that DeBleed is also available as AAX DSP.

Visit Wilkinson Audio for more information.

In Summary

As we stated earlier, opinions are divided on this topic. We feel bleed isn’t as problematic as many engineers make it out to be. For drums, spill often brings extra dimension and depth to the overall sonic picture of drum mixes but there will be times when bleed can cause issues and will need addressing. In such cases, we hope the methods we’ve suggested in this article will help you the next time you feel it is appropriate to reduce or remove spill from your drum recordings.