The main characteristics of a subtractive synthesiser are oscillators, wave-forms (i.e. sine, sawtooth, square, triangle wave, envelopes (i.e. attack, decay, sustain, and release (ADSR)), and filters.

"Electronic musical instrument designed to create a wide range of sounds, both imitative and abstract"

Sine wave: The waveform of a pure tone with no harmonics. Sawtooth wave: So-called because it resembles the teeth of a saw, this waveform contains only even harmonics.

Square wave: A symmetrical rectangular waveform. Square wave contain a series of odd harmonics.

Triangle wave: Symmetrical triangular shaped wave containing odd harmonics only, but with a lower harmonic than the square wave."

Subtractive synthesis is the process of creating a new sound by filtering and shaping a raw, harmonically complex waveform.

Additive synthesis a system for generating waveforms or sounds by combining basic wave forms or sampled sounds prior to further processing with filters and envelope shapers

"Envelope generator with attack, decay, sustain, and release parameters. This is a simple type of an envelope generator and was first used on early analogue synthesisers. This form of envelope generator continues to be popular on modern instruments."

"The time taken for a sound to achieve maximum amplitude. Drums have a fast attack, whereas bowed strings have a slow attack. In compressors and gates, the attack time equates to how quickly the processor can change its gain."

"The progressive reduction in amplitude of a sound or electrical signal over time. In the context of an ADSR envelope shaper, the decay phase starts as soon as the attack phase has reached its maximum level. In the decay phase, the signal level drops until it reaches the sustain level set by the user. The signal then remains at this level until the key is released, at which point the release phase is entered."

"Part of the ADSR envelope which determines the level to which the sound will settle if a key is held down. Once the key is released, the sound decays at a rate set by the release parameter. Also refers to a guitars ability to hold notes, which decay very slowly."

"The time taken for a level or gain to return to normal. Often used to describe the rate at which a synthesised sound reduces in level after a key has been released."

"An electronic circuit designed to emphasise or attenuate a specific range of frequencies." The main characteristics of a sampler are sample rates, resolution, storage, looping, and digital manipulation (i.e. time stretch, pitch shift, reversing, filtering, trimming, etc)

"A digitised sound used as a musical sound source used in a sampler or additive synthesiser"

"Sample rate: the number of times an A/D converter samples the incoming waveform each second."

"Resolution: The accuracy with which an analogue signal is represented by a digitising system. The more bits I used, the more accurately the amplitude of each sample can be measured, but there are other elements of converter design that also affect accuracy. High conversion accuracy is known as high resolution."

Storage: An external sampler’s files are saved on floppy disks, zip disks, or an internal harddrive.

Looping: This is when you define a start and end point of a piece of audio which will then play repeatedly.

Digital manipulation: (i.e. time stretch, pitch shift, reversing, filtering, trimming, etc).

The best examples of samplers and there use are found in software application like cubase and reason.