UnitBasse

Effects · Tremolo

Tremolo for bass:
making the volume pulse

The Tremolo pedal (Ripple) in UnitBasse

A tremolo varies the volume at a steady rate: the note pulses, louder, softer. Locked to the tempo, it becomes a rhythmic effect. Its shape decides whether the pulse is smooth or choppy.

What it does to your sound

Tremolo is the simplest modulation effect: an oscillator turns the volume of your sound up and down at a set speed. It doesn’t touch the pitch or the tone, only the volume.

The shape of the oscillation changes everything: a sine wave gives a smooth, undulating pulse; a triangle, a steadier pulse; a square, a choppy on-off sound that’s very rhythmic.

Locked to the eighth notes or sixteenth notes of the song, it turns a sustained note into a series of rhythmic notes.

Three pulsing volume curves: a smooth sine wave, a steady triangle, and a square that switches on and off.
The volume pulsing, in three shapes (WAVE).
  1. The sine wave: a smooth pulse.
  2. The triangle: a steady pulse.
  3. The square: a choppy, on-off sound.

What it’s for on bass

  • A rhythmic effect: a long note chopped into sixteenth notes.
  • Rock and surf music, on sustained notes.
  • Electronic music, with a square shape, like a sliced-up sound.
  • A gentle, slow undulation, for atmosphere.

The controls, one by one

RATE speed · 0.5 to 15 Hz in UnitBasse

The number of pulses per second. To lock it in: at 120 BPM, 2 Hz gives quarter notes, 4 Hz eighth notes, 8 Hz sixteenth notes.

DEPTH depth · 0 to 100 %

The gap between loud and soft. Low, a subtle undulation; all the way up, the sound cuts out completely between two pulses.

WAVE shape · 0 to 100 %

The shape of the pulse: at zero, a sine wave, smooth; halfway, a triangle; all the way up, a square, choppy.

A starting point

  1. Work out the RATE: the tempo divided by 60 gives quarter notes in hertz; double it for eighth notes.
  2. Set DEPTH to halfway and WAVE to zero for a smooth pulse.
  3. Turn WAVE up towards the square for a choppy effect, and DEPTH up for a stronger one.

The pitfalls

  • A pulse out of time: it makes the sound feel like it’s drifting. Work out the RATE.
  • The groove disappearing: DEPTH at full wipes out part of the notes. In a band, keep it moderate.
  • The square’s click: a very deep square shape can click. Back off a little towards the triangle.

Where to put it in the chain

After the drive pedals, last among the modulation effects, before the delay and the reverb: the repeats and the tail soften the pulse. That’s its place in the classic order.

In UnitBasse

The tremolo is called Tremolo, nicknamed Ripple, in the Modulation family. Its display, Oscillator (2 seconds), shows you the speed and the depth of the movement, and its shape changing as you turn WAVE. No factory preset uses it.

Frequently asked questions

How do I lock the tremolo to the tempo?

Divide the tempo by 60: you get quarter notes in hertz. At 120 BPM, 2 Hz gives quarter notes, 4 Hz eighth notes. Set RATE to that value.

Tremolo or vibrato?

Tremolo varies the volume, vibrato the pitch. People often mix them up, but they sound nothing alike.

Which shape should I choose?

The sine wave for a smooth undulation, the square for a choppy, rhythmic effect. The triangle sits in between.