Portamento

Portamento makes a synth slide between notes. Play C4 then G4 with it off and the pitch jumps straight to G. Turn it up and the pitch sweeps up from C, landing on G after the time you set. The word is Italian for “carrying”, from portamento della voce, the carriage of the voice, a technique singers and string players use to slide between notes. On a synth panel the knob says Glide or Portamento; both names mean the same control.

What the glide time does

• 0 ms: no slide. Every note starts on pitch.
• 30 to 80 ms: a quick slide, the usual range for acid basslines and legato leads.
• 80 to 200 ms: a bend you clearly hear as a bend, like a trap 808 sliding between notes.
• 300 ms and up: slow swoops for sirens and sci-fi effects.

Some synths offer two glide modes. Constant time gives every slide the same length. Constant rate moves at a set speed, so a two-octave leap takes longer than a one-semitone step.

Legato glide

Portamento is most at home on a mono sound, which plays one note at a time. Many synths add a legato (or fingered) mode that slides only when you press the next key before letting go of the last one. Play detached notes and each starts fresh; overlap two and the second slides in from the first. That is how an ordinary synth copies the slides in a Roland TB-303 acid line or the bending 808 bass in trap, as how to make a synth bass shows.

Strictly, a glissando runs through separate notes, like a harpist sweeping across the strings, and portamento is one unbroken bend, like a finger sliding along a violin string. In everyday talk the two words get mixed up.

Lead and bass presets often come with glide already on, and the lead section of types of synth sounds gives typical settings. In Gelato Synth, Glide is a slider on the Osc A page, next to Shape and Level.