Drum replacement might be considered to be an advanced mixing technique, but, in reality, drum replacement can be quite simple to implement with the correct tools and approach. In this article we look specifically at the best approaches to drum replacement, and ask when to use drum replacement and how drum replacement can be implemented in DAWs such as Logic, Pro Tools and Ableton? Before diving in, it’s important to note that we use the term ‘drum replacement’ when often the drums are not 100% replaced, but more likely new drum sounds are introduced and blended in time with the recorded drum tracks, in order to achieve a ‘best-of-both-worlds’ result that combines natural recorded drum sounds and impactful and easily manipulated drum samples.
Drum replacement in modern music production
Music producers of many genres regularly replace or supplement recorded drum sounds with drum samples to make them sound larger than life and to improve the control of sounds in the mix. Improvements can be made owing to the fact that pre-recorded drum samples generally do not have any issues with microphone bleed. Equally, drum samples can often be more easily chosen to have just the right body and decay to the sound, perfect tuning and controlled overtones and a dynamic profile that allows a sharp attack and strong presence – if that’s what is desired. It’s also possible to record drums with trigger sensors attached to the kick and snare if you know that replacement samples will be used in mixdown, which is a very common approach for metal music production. Indeed, Sylvia Massy (Grammy winning music producer/engineer for Tool, Taylor Hawkins and System of a Down) endorses the use of drum replacement when required:
If the kick and snare are weaker than I want, there are many ways to adjust and improve the sound. The easiest way is to augment the kick and snare tracks with carefully chosen samples. The samples are tucked in behind the original tracks to reinforce the sound of the kick, snare and toms. A carefully chosen snare sample can even-out inconsistent playing, or fix a drum that had a tired head.
(Sylvia Massy interviewed for the book Drum Sound and Drum Tuning by Rob Toulson, Focal Press, 2021)
The simplest approach to drum replacement is to create midi tracks for kick and snare instruments (and toms too if desired) and manually position midi-controlled drum sounds to correspond perfectly in time with the drum hits that were recorded in a studio tracking session. In the mix you can then decide on the specific drum samples that you would like to use for replacement and on the volume balance between the recorded drum tracks and the added midi sounds. This can be a good approach also if you want to add some extra frequency components to the recorded sound; for example, an extra layer of sub-frequencies added to a kick drum or a sharp attack sound added to a snare recording. Equally, this can be a good approach to bring a little tighter sense of timing to the track, because the midi samples can be easily adjusted or quantised to be perfectly in time with the click track, if one was used in the recording. The ability to quantise in this way can be limited however, because if the drum recordings are not themselves in time, then flam sounds or other timing incongruence can be introduced, so you’ll need to listen carefully to make sure your midi samples are timed to work well with the real drums.
This approach to drum replacement works well and requires no real expense if you are using a modern digital audio workstation such as Logic, Pro Tools or Ableton, however, it can be quite time consuming, requiring attention to detail of each drum hit and hence becomes open to human error too. To improve the speed and flexibility of implementing drum replacement, there are therefore a number of drum replacement plugins on the market which are aimed specifically at making the task of drum replacement more efficient and less laborious.
Drum replacement plugins
In the early 2000s, the desire for contemporary drums to sound bigger than life or hyper-real had become the norm. Steven Slate capitalised on this demand by producing a CD of well-recorded and hyper-real drum samples, which could be used to replace and enhance those that had been recorded on a tracking session. By perfectly timing a trigger of a powerful kick or snare sample alongside the recorded drum hits, an incredible and impactful drumbeat could be created in the mix. Steven Slate’s drum samples CD was a big success in his home city Los Angeles, so he developed his idea further into the Trigger drum replacement software system (as shown in the figure below). The software works by allowing a user to set thresholds for detecting particular drum sounds, and then using threshold exceedances to play back additional drum samples in time with the original drum hits. With trigger, it’s possible to layer a number of drum samples to create a single sound for each drum hit, it’s also possible to test different sounds easily and to manipulate the threshold analysis to ensure that only the desired drum hits are replaced.
The SPL DrumXchanger plugin takes a similar approach to the Slate Trigger software. DrumXchanger incorporates many of SPL’s renowned Transient Designer features too, allowing drum replacement sounds to be manipulated and crafted to achieve the desired result in the final mix.
Using drum triggers with drum replacement
Drum triggers are vibration sensors using piezo-electric crystals which give off a small voltage when they vibrate. The drum trigger is attached to the side of a drum (usually a kick or snare drum) and the sensor rests delicately on the drumhead. When the drumhead is hit, the vibration causes a sharp, instant signal in the drum trigger. This signal itself is not very musical or representative of the drum sound, but it is perfectly timed in relation to the drumstick hits. Hence drum trigger signals are valuable for either triggering electronic samples during a live performance, or for enabling accurate drum replacement samples to be used at the mixing stage. The Roland RT-30H and RT-30K drum triggers are effective for recording snare and kick signals respectively, and can be connected to a mixing desk via a standard studio DI (direct-injection) box, using a similar approach to capturing a bass guitar or guitar pickup sound via a DI box.
Drum replacement for different genres
Nowadays, a lot of pop, R&B and dance music is heavily weighted towards electronic drum sounds, though some artists have a more hybrid approach that blends electronic and acoustic drum sounds too. So, it’s not uncommon for pop music producers to use significant midi-layering of drum sounds or heavy drum replacement. Conversely, jazz, folk and more classical music rarely utilises drum replacement at all, because the drums are often not required to be significantly prominent in the final mix and authenticity of the recorded sounds is a key objective in those genres. Rock and indie genres tend to sit somewhere in between the authentic and electronic realms, with drum replacement used to make real recorded drums sound a little more impactful, tight, clean or as we sometime say ‘hyper real’. The use of drum replacement can also be a great tool when working on more hybrid genres, such as indie-electronica. For example, a blended kick and/or snare sound using both authentic microphone recordings and classic electronic samples (such as those from the original Roland TR-808 or TR-909 drum machines) can create a combined result that perfectly suits the traditional indie-genre, but equally supports playback in nightclubs and on electronica playlists.
Metal music production is an interesting anomaly from rock and heavy rock with regards to drum replacement, since, like pop and electronic music, metal productions usually use considerable levels of drum replacement to create impactful drum sounds. Often the drum performance on a metal track is so fast and intricate that the bleed caught in snare and kick microphones makes a studio recording very difficult to manipulate well in the mix. It’s not uncommon for metal productions to use drum triggers on kick and snare drums when recording and then use only samples of the preferred metal snare and kick sounds with drum replacement software during the mix. Additionally, the use of drum replacement software allows very consistent hit dynamics to be used, taking away some of the human nuances of a real performance, but delivering a solid and consistent style in the final mix.So it’s certainly possible to record great sounding drums and mix them to a very high standard without the use of drum replacement. For many genres, drum replacement isn’t necessary or appropriate, though in others it is possible to use drum replacement tools to give a valuable enhancement to drum sounds, particularly if they have not been recorded to the standard or style that was hoped, or to support the specific genre of the music that is being produced.
If you want to know more about the underlying science of drumheads and drum sound, and learn more creative approaches to drum sound and drum tuning, check out the free iDrumTune ‘Drum Sound and Drum Tuning’ course at www.idrumtune.com/learn
Author Professor Rob Toulson is an established musician, sound engineer and music producer who works across a number of different music genres. He is also an expert in musical acoustics and inventor of the iDrumTune Pro mobile app, which can be downloaded from the App Store links below: