Virtual Instruments & Synths
Every software instrument is triggered by MIDI — but underneath, some are playing back real recordings, and some are generating sound from nothing at all.
Sample-based instruments vs. synthesizers
A sample-based instrument plays back recordings of a real instrument — a grand piano, an orchestra, a drum kit — triggered by whatever MIDI note you play. A synthesizer takes a completely different approach: it generates sound from scratch using electronic waveforms, then shapes that raw sound into something musical using a chain of building blocks.
A synth's building blocks
Nearly every synthesizer, virtual or hardware, is built from the same core stages. An oscillator generates a raw waveform — the actual source of the pitch. A filter carves away parts of that waveform's frequency content, shaping brightness or darkness. An envelope (commonly ADSR: Attack, Decay, Sustain, Release) shapes how the sound evolves in volume over the life of a single note — a sharp pluck versus a slow swell. And an LFO (Low Frequency Oscillator) can modulate any of the above slowly over time, for effects like vibrato or a rhythmic filter sweep.
Common questions
What is a sample-based virtual instrument?
Software that plays back recordings of a real instrument, triggered by MIDI notes so you can perform them from a keyboard.
What is a synthesizer?
Software or hardware that generates sound from scratch using oscillators, then shapes it with filters and envelopes.
What is an ADSR envelope?
Attack, Decay, Sustain, and Release — the stages that shape how a note's volume changes over its lifetime.
What does an LFO do?
A slow oscillator used to modulate another parameter over time, like vibrato or a sweeping filter.
Hear theory come alive in real instruments
Melody Monkey pairs music theory with real playable sounds — free to try.
Open the free app →Still stuck? Ask Your Personal Music Teacher about Virtual Instruments & Synths →