Modular synthesizer

• VCO - Voltage Controlled Oscillator, which will play a note in a simple waveform (most usually a square wave or a sawtooth wave)
• VCF - Voltage Controlled Filter, which filters out all sounds above or below a certain frequency
• VCA - Voltage Controlled Amplifier, which controls the amplitude or overall volume
• ENV or ADSR - Envelope generator, which is used to modulate an VCA to change the volume of the sound to simulate the volume contour of natural sounds. Because of the modular nature of the synthesizer the Envelope can also modulate other parameters like the cutoff frequency of the filter, so the timbre of the sound can be changed while the sound progresses.
• LFO - Low Frequency Oscillator, from which the output is a low frequency waveform, most usually a sine or triangle wave, usually used as a control for some other module (for instance, to modulate the frequency of the VCO's output)
• Sample and Hold, which takes a snapshot of the input voltage on a trigger pulse and keep it steady even when the input voltage changes.
• Sequencer, which produces a sequence of notes, usually a music loop

• Blacet Research
• Cyndustries
• Doepfer Musikelektronik (A-100)
• Modcan
• Oakley Sound Systems
• Sound Transform Systems (Serge)
• Synthesis Technology (MOTM)
• Synthesizers.com
• Wiard Synthesizer Company

• CSound
• jMax
• MAX/MSP
• pure data
• Reaktor
• SuperCollider
• SynFactory