Having examined the roots of sampling technology, now we're going to look at the more advanced sampling features available on modern samplers and some clever methods for getting the most from your use of samples. A lot of users don't realize the potential to use the sampler as an instrument in its own right, so we'll examine some of the features that make this possible. We'll also see how the advanced functions can be used to take even more control of your sample-based music and along the way, we'll look at some useful tips and tricks for getting creative with the way you use sampled material. The tips here should apply to most software and the majority of hardware, so whatever you're using to sample your audio you should be able to put our advice to good use.
What should a modern sampler include?
The basic standards for samplers these days are higher than they've ever been before. Although the hardware sampler has seriously fallen out of favor, the different options for software sampling are too numerous to mention in full here.
The most successful (and arguably most powerful) software sampler is probably Native Instruments' all-conquering Kontakt package, but most DAWs include some kind of sampler plug-in as part of the package so you can get started without shelling out extra money for another plug-in. Logic's EXS24 and Cubase's HALion are particularly good places to start. These days, even the most basic software sampler will almost certainly offer advanced features including independent pitchshift and time-stretch functions, filters, velocity layers, amplitude envelopes, dedicated filter envelopes, waveform editing, built-in effects, sample layering options and a whole range of MIDI mapping features. The potential is huge.
Although some of these bread and butter features might initially seem uninteresting, they're often incredibly useful for taking control of the sampler as an instrument rather than just a sample playback device. Take, for example, filtering. From the first samplers of the 1970s and '80s, filters have been included as a basic part of the sound-shaping arsenal. Many of the earliest machines included analogue circuits but the market later moved to digital filters in order to reduce costs. As with filters in synths, analogue circuitry is usually considered more desirable here. The filters in your software sampler are likely to offer flexibility which could only have been dreamed of two decades ago, and the filter section is a seriously powerful and often underused tool.
Think of the sample itself as the basic building block of a more complex synthesis process and the filter can be used to shape the sound to fit your track just as you'd use a filter in a synth to create a sound. Most samplers will allow the filter to be controlled via an envelope, so it can even be manipulated over the course of your sample, allowing an even greater flexibility when it comes to tone shaping. These basic features shouldn't be overlooked when it comes to their ability to tweak your samples.
With modern samplers, time-stretching without affecting pitch is almost taken for granted. However, the earliest samplers offered no way to separate the process of pitch-shifting from time-stretching. Samples were simply played back faster to pitch them up and slower to pitch them down. As a result, it was impossible to adjust the pitch of rhythmic samples without affecting their speed, or match the tempo of a loop to your track without affecting its pitch. It was mainly thanks to Akai's research and development of digital audio processing techniques in the late 1980s that time-stretch features were brought to the mass market. With the ability to adjust pitch and time independently, it's simple to make sure that your samples fit your track rhythmically and harmonically, whereas previously, it could be fiddly to ensure that both were correct. Luckily, it's easily achieved with any modern sampler.
With contemporary time-stretch technology, not only can you adjust pitch and speed independently, but the two can even be adjusted in opposite directions simultaneously. Interesting effects can be achieved, for example, by pitching drum samples down while also speeding them up. The resulting deep but snappy sounds can be used to create unusual percussion tracks.
Ironically, these days it's probably easiest to get a unique sound by going back to the old methods, with pitch and speed being manipulated together. For instance, a classic ravey sound can be achieved by pitching a vocal up from, say, lOO bpm to fit a 130 bpm track, giving it the chipmunk effect. It's a surprisingly effective technique which is easy to achieve in just about any sampler.
Resampling refers to a number of related processes which can be used to manipulate sounds. In essence, resampling is the process of making a new sample from an existing one. The most basic example would be to take a sample, let's say of a drum loop, and re-record it at a different sample rate in order to achieve a different sound. There are many reasons why resampling can be useful, whether for creating unique sounds or simply for practical purposes such as using your computer efficiently. For example, if have a loop which you're processing with EQ, effects or other plug-ins, it's possible to resample it so that all of this processing is included as part of the audio recording rather than added each time the sample is triggered. If carried out correctly, the resulting resampled loop has exactly the same sound but takes up much less of your computer's processing power.
Clever use of resampling can also be used to create radically different sounds to the original sample. Let's say we run a synth bass note through a low-pass filter and resample the filtered sound. If we then trigger the note at different pitches, the cutoff frequency of the filter will appear to be pitched up and down with the note itself. The result is a seriously easy method of creating a key-tracking filter effect.
Similar effects can be achieved with filter envelopes, giving resampled notes some of the characteristics of tempo-synced filters. The potential of resampling is huge, with the results often sounding quite unlike any other way of working.
What about sample packs?
In the early days of sampling, it was a huge chore to create your own sampler patches from scratch. Recording audio into a hardware sampler and editing waveforms on a tiny LCD screen made it time-consuming and fiddly to create complex setups. As a result, a number of companies spotted the gap in the market for ready·made sample packages supplied on CD. The sample library industry was born and thrives to this day. If you're just trying to sample effects, occasional drum hits or even vocals, it's unlikely you'll need to exploit the full range of sample playback features on offer. However, recreating instruments is a much more complex task. If you have the patience to sample every single key of a grand piano (along with a number of variations of expression for each note), edit each sample and create a custom sampler patch of your own then we salute your tenacity. For the rest of us, buying a ready-made sampler instrument is a much easier option.
Chop and Change
When dealing with loop-based samples, there's a great temptation to grab a simple loop and repeat it. However, things get much more interesting when you step out of this comfort zone and start to chop and edit your loops.
Sampling workstations like the Akai MPC range make loop chopping easy with automatic editing functions, but the same principles apply with any hardware or software sampler, either by manually editing each slice of the loop or through an automated function such as Logic 9's new Convert Region to Sampler Track feature. This is a great example of an automatic sample slicing tool. The audio is analyzed for transients and then split into sections wherever a beat is detected.
These slices are sent to a new sampler instrument, with each slice assigned to a note and a MIDI region created to play back the original loop using the samples. It's an easy tool to use but it's also one of the most powerful ways of manipulating samples. Check out our example on the DVD to see how you can use it to quickly and easily chop a drum break into sections.