Introduction to Sampling Page 4/5
You have your sample neatly trimmed and looped, so what else can you do with it? You can filter and envelope it for a start. You can time stretch it. You can layer it, and arrange it and other sounds out across the keyboard.
With sampling, the fun doesn't really start until you begin creating a complete keyboard set-up. So far we've looked at single sample edits. Now it's time to put all these tips together to create a multi-sound performance.
It's very rare for single samples to be used unaltered. It's more usual for them to be combined in groups, filtered, switched, and otherwise interfered with, to create sounds with a whole range of expression options.
One of the best things about samplers is the way you can use them to play the same sound while creating completely different effects. By adding synth-style filters and envelopes you can change a string sound from creamy dreaminess to pizzicato plucks - which gives two sounds for the price of one sample.
This works really well with percussive sounds. Tune a Roland TR-808 bass drum up high and you get an electro-tom 'pew' sound. Tune it low and you get the original bass drum effect. You may cut off the long decay with an envelope, making a much tighter and more percussive effect. Filtering can also be used to tidy up noisy samples, and to bring out speech from a background of noise. If you turn down the filter setting on a hissy sample, you'll often be able to enhance the rest of the sound and make it stand out. Adding some resonance with a filter cut-off somewhere between 1KHz and 4KHz will emphasise speech and vocals.
Another good trick is to use the same sound with different filterings at different tunings. The same hi-hat sample can be used to make a high-pitched 'tick' noise and, when heavily filtered, a squishy sample and hold effect. You can even make a bass sound double as a pad. Add a spiky envelope and a snappy filter sweep for a punchy bass, and a slow envelope with a low filter cut-off for a pad sound based on the same sample.
Multi-samplesMost of the time you will set your sampler up to play multi-samples. The useful range of a drum loop is only an octave or two. Anything more is a waste of keyboard space, and you could be using this for other sounds.
This is especially important when sampling acoustic instruments. There's a huge difference in harmonic quality between the lowest and highest notes on a piano, it will be necessary to simulate this to create an accurate piano sample. This is achieved by sampling the sound of notes at different octaves - or, if you want a totally realistic sound then the notes themselves. Then you lay all these samples out across the MIDI keyboard range on a single MIDI channel to recreate the original effect.
Multi-sampling may be utilised to create drum maps. Each sound can have a note, or perhaps a range of notes, assigned to it. Then when you play the notes on the keyboard you get a different sound on each one.
Hit the switchAnother important option you should know about is velocity switching. With this you can assign different samples to the same note, and switch between them depending on how hard you've hit a key. With some samplers you have the option of crossfading rather than switching, so that as one sample gets louder another gets quieter, both keyed to velocity.
Velocity switching is great for adding expression to your music. You can change a bass sound into a slap by switching between two samples, or add a quiet percussive 'thunk' to a piano sound that becomes more obvious as you play harder. Some professional string sample libraries use lots of velocity switching and crossfades to create some spectacularly realistic effects.
Mix and matchNew effects can be created by layering sounds (which is how most digital synths work). The sky's the limit with this one - the only restriction here could be your imagination.
There are two ways to create a layer effect. You can create two keygroups that overlap, so that when a note is played, both samples can be heard at once. In theory you can overlay as many keygroups as you like to create a really huge sound, but in practice you're limited by your sampler's polyphony. You can get round this by layering up a huge stack of sounds and playing it out to DAT, and then resample it.
All of the same tricks that you would use to make big sounds on a synth apply to samplers too. You can use different samples for the attack and sustain portions of a sound, crossfading between sustained sounds by routing the LFOs to the sample level and filter cut-off. You can also add a slightly different vibrato effect to each layer to create a shimmering chorus, or alternatively, make two copies of a layer and offset the pitch very slightly up and down to create another version of the same effect.
The other option at your disposal is to mix two or more samples together. This can be fun with drum sounds: you can mix up a storm of a snare sound by taking all the snares in your sampler's library and piling them on top of each other. Mixing samples, as opposed to keygroups, doesn't eat up polyphony, but it's much harder to edit sounds this way - it takes longer, and lacks the same degree of control.
You can't, for example, add separate filters and envelopes to each layer in a sound. But you can create special effects. Aside from being handy for making monstrous beats, sample mixing is a good way of creating rich pads. Just copy the sample, splice empty space in at the start to add a delay, and mix in the original.
The big pictureOnce you have your keyboard layout, with all the stacks, layers and switches sorted, you can stack different layouts together to create a complete MIDI performance. This is where you assign different keyboard layouts to different MIDI channels: for example, drums on channel ten, a loop and a bass line on channel one, and so on. A quick and dirty way to layer performances without messing around with keygroups is to set two or more to respond to the same MIDI channel. As with any other kind of layering, you have to be careful about polyphonic considerations. Each time you use a layer you halve the effective polyphony. Use a 4-layer stack on a 32-note sampler and you're down to 8-note chords.