Component
Vibe
v0.5.108
Modulation effects & EQStereoVintage
Uni-Vibe: four phase stages around one lamp, a lopsided, breathing sweep.
Software v0.5.108
Overview
Uni-Vibe: four phase stages around one lamp, a lopsided, breathing sweep.
A modulation effect in the style of the Uni-Vibe family and its modern clones. It is not an ordinary phaser: the sweep is lopsided and pulsing, it breathes rather than ticks. Mono in gives stereo out.
Mode Chorus mixes dry and wet signal for the classic sound, between chorus and phaser. Vibrato is wet only, so the phase shift pulls at the pitch. Light is a clean delay-line vibrato without the lamp character. Speed and Intensity have CV inputs; an expression pedal or envelope on Speed does what the foot-pedal version of the original did.
Controls
| Control | Range | Default | What it does |
|---|---|---|---|
| Speed | 0.1 … 12 Hz | 2 | How fast the lamp pulses. |
| Intensity | 0 … 1 | 0.6 | How deep the sweep goes. |
| Mode | Chorus / Vibrato / Light | Chorus | Chorus = dry + wet (the classic sound), Vibrato = wet only, Light = clean vibrato. |
| Lamp age | 0 … 1 | 0.7 | How much lamp and LDR character: 0 = a clean sine sweep, 1 = the lopsided sweep of an old unit. |
| Volume | 0 … 2 | 1 | Output volume (up to 2). |
Ports
| Port | Direction | Signal | What it carries |
|---|---|---|---|
| S+ | in | cv | CV for Speed, for example an expression pedal or envelope. |
| I+ | in | cv | CV for Intensity. |
| L | in | audio | Left input. |
| R | in | audio | Right input; leave empty and the left input feeds both sides. |
| L | out | audio | Left output. |
| R | out | audio | Right output. |
How it works
Four phase-shift stages each use a different capacitor (15 nF, 220 nF, 470 pF and 4.7 nF), so the notches are spread widely over the spectrum instead of sitting in a neat row. All four stage resistors are light- dependent resistors around one small bulb, driven by an LFO. The bulb's brightness goes roughly with the square of its current, and the LDRs turn low-resistance quickly when the light comes on (about 6 ms) but recover slowly in the dark (about 60 ms). That gives the skewed, throbbing sweep.
Lamp age sets how much of that character is present: 0 is a clean sine
sweep, 1 the lopsided sweep of an old unit. In Light mode a delay line is
modulated by a sine between 0.5 and 6 ms, wet only. The same C++ kernel
(mmb_dsp/vibe.h) runs on the Teensy and in the browser.
Runs on
- Teensy 4.1 (the MusicBrain Brain): about 5.1 % CPU per instance (one note, default settings), measured on firmware 0.5.108.
- The browser: the editor's simulator runs the same C++ code as WebAssembly, so what you hear while patching is what the Brain plays.
Try it
In the editor's example set: 💡 DX7 + Vibe.
Editor: https://editor.musicbrain.nl
Sources & licences
- Own implementation (MIT licence), modelled on the Uni-Vibe circuit family (four phase stages with LDRs around one lamp), including modern clones such as the Mojo Vibe.
Versions
- 0.5.78: the
lampcontrol renamed to Lamp age. - 0.5.73: first version: four phase stages, lamp and LDR behaviour, Chorus, Vibrato and Light modes, Speed and Intensity CV.