The processes involved in sampling a drum machine (or any other instrument for that matter) will vary dramatically depending on what it is you are trying to achieve, or what your end goal is.
Are you aiming to capture the exact sound and nuances of the original machine? Is the drum machine analogue or digital? Maybe you simply want to expand your collection of single hit drum sounds? All of these things may affect the way in which you approach the sampling process. With Drum Machines 02 for instance our end goal was to develop "A modern take on a classic sound".
808 and 909 samples aren't hard to come by; a quick search of Google will return zillions of websites claiming to offer 'the most awesome' sounding TR-x0x samples. Drum Machines 02 is not a groundbreaking library by any means - but then it's not supposed to be either... What we did (and hopefully achieved well) is offer our own take on these classic drum sounds.
Our approach was to take the raw audio output from these machines and modify or modernize it through the use of creative signal processing and sample layering techniques.
Our free sample pack 606 Drums on the other hand required a different approach altogether. Our main aim here (with the dry kit at least) was to capture the true sound of the 606 along with all its nuances and inconsistencies. Recording multiple round robin variations and velocity layers for each drum hit enabled us to produce a pretty damn true to the original sounding 606 drum kit...
Round Robin SamplingIn a sampler, round-robin means to play back several sampled variations of the same sound each time you hit the same key, the aim of which being to emulate the inconsistencies in acoustic sound, or in our case analogue electronics.
Think about how the tone varies when a drummer hits the skin of a snare drum - no two hits will ever sound exactly the same. If you were to sample just one single hit from an acoustic snare drum and then use this sound in your sampler to create a snare roll for example, you would be left with a very static 'machine gun' type effect that would sound far from a 'real' acoustic drum.
This is also the case with analogue oscillators or drum machines. Because of a drum machine's analogue nature, subtle differences in tone are heard in the sound each time a drum is triggered. This means that no two hits coming from the drum machine will sound exactly the same, which in turn makes the overall sound a lot less static and instead, more vibrant and real. This is one of the reasons why people prefer the so called 'analogue' sound.
With 606 Drums we felt it necessary to record up to 8 "round robin" samples per sound, to help capture the 'movement' created by random analogue behaviour. When our 606 drum kit is played back from a sampler supporting round-robin playback, each sound within the kit will periodically cycle through eight different variations of the same hit each time the same key is pressed.
If you repeatedly hit the snare drum key within our kit for example it will cycle through playing back:
Snare Variation 1, Snare Variation 2, and Snare Variation 3 all the way up to the 8th variation, before cycling back to the 1st variation. So essentially the snare drum will need to be played eight times before it sounds the same as it did the first time the key was pressed.
Round-robin is an important part of sample instrument design and is used extensively by developers emulating 'real' instruments, hence the reason some Kontakt libraries require an enormous amount of hard disk space!
The Recording ChainAssuming for a moment that you will be recording (or sampling) the drum machine sounds to your computer; you are going to need to make a few decisions on the recording chain or path the sound should take before being converted to a digital form. If you have a collection of hardware or outboard signal processors you may want to experiment with 'shaping' the sound further before hitting the A/D converters.
Using a compressor with a fast attack and release can be used to smooth out any sharp transient attacks that may be eating up too much headroom. A fast attack will ensure that the compressor 'captures' the initial transient whilst a quick release will ensure that not too much of the sound's 'body' is compressed. The desired amount of gain reduction can be set by using both the ratio and threshold controls. Finally the compressor's make-up gain can be used to bring the volume back up to a sensible level. The result will be a consistent and overall louder sounding drum hit.
Setting a fast attack and long release along with a very high ratio and aggressive gain reduction can dramatically affect the bass response and punch of a sound, which of course 'may' be something that you are trying to achieve.
Alternatively compression may be used to emphasize the transient attack of a drum sound. This will make the sound appear more punchy and aggressive. Setting a relatively slow attack time of between 10 and 50ms with a ratio of around and above 4:1 is a great starting point to add punch to your drum hits. Experiment with different release times to shape the body of the sound.
Longer release times will perceivably sustain the body of a sound and with extreme settings will cause the drum hit to sound 'squashed'.
Shorter release times will cause a drum hit to 'pump' which in turn can be used to heavily shape the aggressiveness and perceived loudness as the compressor quickly falls back below the threshold and the sound is brought back to its pre-compressed volume.
Other Things to ConsiderEQ is your friend, use it to reduce muddiness, cut out unwanted frequencies or emphasize certain frequencies of a drum sound. I will often use two EQs in series whilst still in the analogue domain, before hitting the AD (analogue to digital) converter. The first of which may be used to filter out unwanted frequencies (corrective EQ) whilst the second may be used (if desired) to creatively alter the sound in a pleasant way. This may mean slightly reducing the frequencies around the mid-range area and boosting a couple of dB at 6 KHZ for example.
Most of the time I am using EQ at this stage to simply clean up the sound. Finer EQ adjustments can be always be made at a later stage in post production or mix down. I will also often use EQ to add 'character' to a drum sound. The famous Pultec EQP1 equalizer for example allows one to boost AND cut the same frequency simultaneously, in turn creating a resonant shelf. I often use our A Designs EM-PEQ (Pultec style EQ) on kick drums. Simultaneously boosting and cutting at its 60HZ setting can sound wonderful on certain kick drums and can drastically change the character of the sound.
Each EQ (or compressor for that matter) has its own unique sonic character. Understanding our tools and knowing how and when to utilize these different characters is one of the ways in which we are able to achieve our drum sound. It's kind of like painting a picture with sound.
Watch Your LevelsIt is very important to keep an eye on you metering, especially so when recording to a digital medium, typically your computer. Recording a sound into your soundcard (converters) at a very low level and then increasing this volume digitally via your DAW software will bring up the noise floor. This is something you will want to avoid if possible.
Record a sound too hot (loudly) and you may introduce digital clipping and all manner of nasty artefacts once the signal passes through the AD converter.
At Wave Alchemy we record all of our samples in 24-bit. The downside to 24-bit recording is bigger file sizes and less compatibility, although this isn't a problem at all in this day and age!
To obtain an extremely detailed understanding of bit-depth and digital audio in general I would highly recommend reading John Watkinson's 'The Art of Digital Audio'
Using a Pre-ampWhen recording drum sounds for our libraries, I will often use a pre-amp. Different pre-amps may be used depending on what I am trying to achieve. As with EQs and compressors, pre-amps will often have their own unique sonic character. A vintage Neve pre-amp for example may give a softer, creamier sound whilst an API unit will give a cleaner and extremely punchy sound.
To avoid amplifying our sounds digitally I will often use a pre-amp to boost the gain of the signal before hitting the AD converter, especially so when recording older analogue machines that may have an extremely low output level. This is also the case when processing the output of a drum machine with a compressor for example. If the said drum machine has an ultra low output level a pre-amp can be used to boost the signal going into the compressor which can allow the compressor to be operated at its optimum level.
Recording a Sound TwiceSignal processing a drum machine on the way into the computer is of course a non-reversible process. That is, once recorded you are then 'stuck' with the EQ or compression settings you have applied. You have essentially printed these settings as part of the sound.
When creatively processing a sound as part of the recording chain we will usually record a duplicate of this sound without any of the signal processing applied. This is achieved by simply bypassing the processing chain and recording the duplicate sound dry. The sound will usually be given the same name as the processed variation but with _dry at the end of the file name. This of course gives you the option to process the sound at a later date without having to worry about it already being altered.
Taking Things FurtherOnce recorded, we will often use techniques to further alter or tonally shape the sound of a drum hit (if required or desired or course).
Drum Tools 01 library. Layering can be used to simply fine tune a sound or, more commonly, to create a completely new drum sample from several sound sources.
Drum layering is a technique that I plan to cover in a future blog post so please get in touch or add a comment below if there is something specific you would like me to include...
Be creative and stay tuned!
Written by Dan Byers of Wave Alchemy