SAMPLING

Sampling

When part of a song, single note or sound is reused in another context.

Common to use a sampler to either record, manipulate or playback audio material.

Technique of using everysay noises in music began with Musique Concrete in 20th experimental Century.

Tape recorder and early sampling (Pre 60s)

• Main instrument for early Muique Concréte composers

• Process formed the bass for modern-day Sampling.

Tape recorder and early sampling - Techniques

• Cutting and splicing the tape,

• Making loops

• Reversing altering the speed of playback

• Layering sounds

Tape recorder and early sampling - Limitations

Impossible to change the speed of playback without altering the pitch

Sampling instrument - Mellotron (1962)

• The first achieved widespread acceptance as an early sampler.

• Used different banks of pre-recorded tapes (one tape strip for each key)

• Gives several choices of sounds (including strings, brass, flute and choir)

• It was expensive and notoriously fragile.

Digital Samplers as instruments

• Samplers can record audio either as one-shot, single note samples or short loops / musical excerpts

• Can store audio ready for playback or apply processing and sample manipulations

• Early samplers had limited memory in which to store samples so bit depth and sample rate was lowered.

• Early samples sounded lo-fi which can be emulated by DAW

• Modern Samplers often feature controls similar to synths such as LFOs and envelopes

Drum Machines

Drum machines embraced early sampling technology. Samples required were short and a single pitch and did not take up much memory

• Roland TR-909 used sample cymbal sounds which greatly improved the realisms of the sounds compared to those synthesised on the TR-808.

Historically important samplers

• Fairlight CMI (1979) - Cloudbusting (vocal sample in bridge)

• E-MU Emulator (1981) - Died in your arms tonight (opening phrase)

• AKAI s900 (1986) - Out of space

• E-MU ESI Series (1994) - Homework

• Nemesys Gigasampler (1997)

Making samplers realistic

• Common to see samplers as software instruments on DAW

• If sampling a real instrument, in order to to be played on the keyboard, three key techniques are required:

  • Keyboard Tracking

  • Multisampling

  • Velocity layering

• When done well, can be impossible to tell that a sound source is sampled,

• Bad sampling can introduce artefacts such as clicks when a loop point is badly chosen

Making samplers realistic - Keyboard Tracking

• Spreading a single sample out across the keyboard

• Sample is pitch-shifted in response to the key played

• Noticeable when a sound is pitch-shifted beyond a few tones

Making samplers realistic - Multisampling

• Taking a sample every few notes and mapping across the keyboards that samples are pitch-shifted across a smaller range of notes

Making samplers realistic - Velocity layering

• Switching between a number of different samples depending on the MIDI velocity of the note

Zero crossing editing

• It is important to cut samples at a zero crossing point to avoid creating a click

• Can also fade the staples in and out or use crossfade looping

Loop Points

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Types of crossfade

• Fade can be used to avoid a click when it is not practical to find a zero crossing point for a sample audio edit.

• Crossfade can be used to fade between two different samples, audio regions or loops.

• There are different types of crossfades:

  • Equal Power crossfade

  • Linear Crossfade

Using synth parameters on samples

Controls include:

• Filters

• LFOs

• Envelopes

• Changing the octave

Manipulating & altering samples

• Loop - Repeats the sample

• Transpose - Changes starting pitch / key of sample

• Normalise - Increases the volume to max without distorting

• Stuttering - Repeating small parts of sample to create a ‘stutter’ effect

• Gapping - Adding spaces between small parts of sample

• Reverse -Playing sample backwards

• Time stretch - Slowing or speeding up the sample. Can also decrease and increase pitch

• Pitch shift - Move entire sample up or down in pitch. Can decrease and increase playback speed

Destructive and non-destructive editing

• Destructive editing changes the audio file associated with the sample; Processing is not normally reversible. Normally, editing in a DAW sample editor is destructive. Physically making changes to a tape is another example of destructive editing

• Non-destructive editing does not change the audio file, and effects or processing are normally easily removed. Channel strip plug-ins used as inserts and send effects are non-destructive.

Software samplers

-Musicians still struggle with reliability of software-based equipment when touring, so despite the capabilities of software, hardware still has its place in the working musician’s gig bag.

-Line between synths and samplers has become gradually more blurred, as many synths provide sample playback or integrate fully-fledged samplers and can use sampled waveforms as basis of their synth engines.

-Can use synth functions such as filters, envelopes and LFOs to manipulate samples, in effect replacing the oscillator with a sample as a sound source.

-Also possible to apply sampling techniques in the arrange window in a DAW, which can sometimes provide more flexibility in editing and manipulating a short extract of audio.