Making a Custom Sampler Instrument

Sampling is one of the most important aspects of modern music production. It is the basis of the sampler, one of the most common types of software instruments. Many software emulations of real instruments, like string, horn, and woodwind plug-ins, are possible through sampling and samplers.

The sampling process is relatively simple, and using this process we can create a new instrument out of nearly any sound.

In this article, we’ll go over the general process to create a custom sampler instrument. We’ll discuss everything from the simplest setup to full multi-sampling. As demonstration along the way, we’ll create a custom instrument from a percussion hit and a realistic-sounding piano.

A brief history of sampling

Sampling, by definition, is simply repurposing existing audio. As early as the 1940s, musicians have been using existing recordings as musical material in new projects.

Check out this infographic, which shows the use of sampling by genre over the past century.

You’ll notice that, on most of the graphs, there is a sudden increase in sampling between the 1970s and 1990s.

During this time, the development of cheap sequencers and samplers allowed for musicians around the world to sample audio on their own. This accessibility resulted in an explosion of art and the study of previous musical traditions. The origins of hip-hop and electronic music (sampling genres like soul and R&B) are deeply rooted in these advancements.

Given how prevalent hip-hop and electronic trends are in modern music, sampling could very well be one of the most influential advances in music.

During their development, samplers themselves have taken many forms. The first samplers were designed to function similarly to wavetable synthesizers, using a sample of the wavetable as source audio.

Others were used in a looping context, used to record and play audio back in a performance setting.

Drum machines, which were monumental in the development of hip-hop and electronic music, function as samplers. Each pad was able to fire off different percussive or melodic samples, allowing for new possibilities like live remixing and the creation of custom drum kits.

The most involved type of sampler emulates a realistic-sounding instrument. This can be done with simple audio samples of the instrument, allowing any average producer to create custom instruments.

Developers for high-quality sampled instruments may even use a combination of sample playback and synthesis to recreate these types of instruments.

Our main focus today will be these sampler instruments with melodic capabilities. We’ll be working in Ableton Live’s Simpler and Sampler plug-ins, as well as the sampler in Native Instrument’s Kontakt. Don’t worry if you don’t have access to these plug-ins; all of these functions are common in the average sampler.

Basic samplers: one sample pitched

In the simplest terms, a sampler instrument functions by firing off a sample at different pitches.

We can play audio at different pitches. Pitch can be changed by playing the audio file at different speeds. Therefore, the simplest sampler would have one sample, which is pitched relative to playback speed.

We’ll be demonstrating this process with Ableton’s Simpler plug-in and this percussion hit:

With this setup, the audio sample is pitched by the sampler using this playback speed approach. Notes that are higher than the original sample’s pitch will sound shortened, while notes lower will sound stretched. This results in audible differences in note length, which are especially noticeable at the extremes of the keyboard.

For some purposes, this could be perfectly viable. But a real instrument wouldn’t react this way. It would be more accurate if the sample could be pitched without the sample duration being affected.

Thankfully, with a process known as granulation, this is possible. We won’t dive too deeply into granulation in this article, but it is able to effectively decouple pitch and playback speed. This way, independent pitch-shifting and time-stretching is possible.

Ableton’s audio warping features and Kontakt’s sampler use granular processes to do this with audio samples.

By engaging the “Warp” mode on Simpler, the percussion hit will change pitch without getting shortened or stretched. The sample will be pitch-shifted to play other notes. Our sampler now acts more like a playable instrument, and seems to respond more accurately to MIDI input.

Now, the length of notes will be mainly determined by how long the note is held and the amplitude envelope settings.

Basic samplers: adding sustain

As this is a percussion sound, it’s not a problem that we can’t sustain each note. However, other sounds like keys, strings, and horns should have the ability to sustain.

Some samplers allow us to do this by looping certain sections of the sample. A sustained sound will output a relatively consistent waveshape, therefore looping a waveshape could theoretically mimic the sound of a sustained note.

Let’s test this out with our percussion sample. Because the percussion sample is a transient drum hit, there is not an obvious repeating waveshape to loop. This will make it easier to hear how the sample is being looped.

We’ll be using Ableton’s Sampler for this, a slightly different sampler than Simpler, which has access to the looping functions that we’re after.

In Sampler, we’re able to set Sustain and Release modes for the sample. Based on MIDI input, certain sections of the sample will occur and / or loop.

I set the sampler to play the beginning transient in the sample as normal. Then, as a MIDI note is sustained, the tail of the percussion hit is looped. This is smoothed out with crossfades. Once the MIDI note ends, the release phase begins, and the rest of the sample after the loop plays.

Looping allows us to create a sort of sustain that responds to MIDI input, and the release phase creates a natural-sounding tail after the loop.

Sampler gives us a couple options for the Sustain and Release modes. Either section can restart at the beginning or perform a ping-pong loop going back and forth. The two examples below have normal and ping-pong looping respectively during the sustain phase.

Notice that, with a percussion sample like this, higher notes have a bit of a stuttering effect. We can create a shorter loop to “sustain” these higher notes.