Unison

Unison is the simplest intervalIntervalThe distance in pitch between two notes.View full entry → — a distance of zero semitones — and occurs when two or more parts produce the identical pitchPitchThe perceived highness or lowness of a sound, determined by its frequency.View full entry → at the same time, or when multiple performers play the same melodic line together. Orchestral passages marked "a2" or "unisonoUnisonoIn unison — all performers playing or singing the same notes together as one voiceView full entry →" instruct an entire section to play the same notes, producing a powerful, blended sound with enhanced volume and richness from the slight timbral differences between instruments.