Samplers Flashcards
The tape recorder and early sampling
They would use tape to capture sounds and then manipulate them by cutting and splicing the tape, making loops, reversing the playback, altering the speed of playback and combining/layering sounds
There were limitations to what could be achieved with tape, for example it is impossible to change the speed of playback without altering the pitch
This process formed the basis for modern-day sampling and the 1960’s saw the first instruments used in pop music that could play back samples
Digital samplers as instruments
Samplers can record audio either as one-shot, single note samples or as short loops/musical excerpts
They can then store this audio ready for playback or apply processing and sample manipulation
Early digital samplers had limited memory in which to store samplers and thus the bit depth and sample rate were lowered, making the samples sound lo-fi
Bitcrusher plug-ins in a DAW create a lo-fi effect in the same way by lowering the bit depth and the sample track rate
Drum machines embraced early sampling technology, the samples required were short, at a single pitch and thus did not take up much memory
The Roland TR-909 used sampled cymbal sounds, this greatly improved the realism of the sounds compared to those synthesised on the TR-808
Modern samplers often feature controls that are similar to a synthesiser such as LFO’s and envelopes
Historically important samplers
Fairlight CMi- 1979
E-Mu Emulator-1981
AKAI S900-1986
Emu Esi Series-1994
Nemesys Gigasampler- 1997
keyboard tracking
Spreading a single sample out across the keyboard.
The sample pitch-shifted in response to the key played: however, it is noticeable when a sound is pitch-shifted beyond a few tones
Multisampling
Taking a sample every few notes and mapping across the keyboard so that samples are pitched-shifted across a smaller range of notes
Velocity Layering
Switching between a number of different samples depending on the MIDI velocity of the note
Zero Cross Editing
it is important to cut samples at a zero crossing point to avoid creating a click: you could also fade the sample out or use cross fade looping
Making Samples realistic
If sampling a real instrument, in order for it to be played on the keyboard at various pitches, three key techniques are used to make samples sound realistic
when done well it can be impossible to tell that a sound source has been sampled, just as it might be impossible to spot a well executed edit in a multi-track recording
When done badly sampling can introduce artifacts such as clicks when a loop point is badly chosen
Types of Crossfade
A fade can be used to avoid a click when it is not practical to find a zero crossing point for a ample audio edit
A crossfade can be used to fade between two different samples, audio regions or loops. There are a number of different types of crossfade such as Equal power crossfade or a linear crossfade
Using synth parameters on samples
The key difference between a sampler and a synthesiser is that a sampler uses an audio source as it’s starting point rather than a tone produced by an oscillator on a synth
Samplers often incorporate similar controls to those you might see on a synth
Such controls might include filters, LFOs and envelopes, along with the ability to change the octave and route parameters in different ways.
Manipulating and altering samples
Loop-Repeats the sample
Transpose- Changes the starting pitch
Normalise- increase the volume to the maximum without distorting
Stuttering- repeating small parts of the sample to create a stutter effect
Gapping- adding spaces between small parts of the sample
Reverse- playing the sample backwards
Time stretch- slowing down or speeding up the sample. on tape and on many digital samplers, slowing the sample down will also decrease the pitch and vice versa
Pitch shift- Moving the entire sample up or down in pitch. On tape and on many digital samplers, a higher pitch will result in a faster sample playback
Destructive editing
this 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
Non destructive editing
this dose 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-destructible
Loop points
Looping is a technique that stems from the days when samplers had tiny memory stores in which to load samples. Many sounds start off with complex attacks but soon settle into a more or less steady waveform. By repeating this “settled” area, a sample can be sustained indefinitely without using up limited memory space. Even with modern software samplers that have access to gigabytes of memory looping is a useful technique to create sustaining sounds out of samples that are otherwise quite short.
Zero crossings
‘Zero crossing’ refers to identifying a point in the wave form where there is no signal - the wave is effectively static and therefore no sound is being generated. These are therefore logical points at which to cut a wave as they should not results in any ‘pops’ or ‘clips’ as an audible sound is cut-off abruptly.
