ADSR ADSR Attack, Decay, Sustain, Release, abbreviation for the so called ADSR-envelope that forms a shape which controls voltage controlled circuits like amplifiers or filters. Attack Decay Envelope Sustain Release Attack time value, time span defined for an envelope to rise after starting the envelope cycle ADSR Decay time value, time span defined for an envelope to fall after rising to a hold state ADSR Envelope Definition of time and level values to shape a signal. Most common structure is a so called ADSR-follower. Such an envelope has a rising Attack-time, a first falling Decay time leading to the Sustain level. At the end of the cycle there's a Release time, damping the signal's strength. For example a piano has a rather short Attack time, no Sustain level and a Release time. Strings have varying Attack times as well as varying Decay, they have a Sustain level and very flexible Release time. ADSR LFO Low Frequency Oscillator, an oscillator with very low frequency, typically below 10Hz. Often used with VCAs or VCFs to shape a signal. VCA VCF Release time value, time span defined for an envelope to fall at the end of an envelope cycle ADSR Sustain strength or level value, level of an envelope while being in hold state of an envelope cycle ADSR VCA Voltage Controlled Amplifier, an amplifier whose amplification depends on a controlling voltage. Instead of making it louder by turning a knob you raise the controlling voltage. Often used in conjunction with Envelopes or LFOs to shape a signal. Envelope LFO VCF VCF Voltage Controlled Filter, a filter whose parameters, for example cutoff frequency, depend on a controlling voltage. Instead of changing the frequency by turning a knob you raise the controlling voltage. Often used in conjunction with Envelopes or LFOs to shape a signal. Envelope LFO VCA