The term vocoder is a portmanteau of voice encoder, a device originally developed by Bell Labs as part of a military device used for scrambling and encoding of voiced messages during World War II. A Vocoder usually consists of a transmitting, analysis part and a receiving, re-synthesis part. The signal input into the vocoder analyzer is called a modulator and the signal modulated in the re-synthesis part is called a carrier. The analyzer part breaks down the input signal to a number of frequency bands. Each analyzer band sends information about its state to a corresponding band in the re-synthesis part where this information is applied.
This old military device was picked up by the music technology business in the late 60s and spawned a multitude of different hardware and software versions used and made famous by artists like Herbie Hancock, Jean-Michel Jarre, Phil Collins, Laurie Andersson and Africa Bambaataa just to name a few.
In the Softube Vocoder, the input audio signal is the modulator which affects the built-in carrier synth which can be controlled via the on-screen chord keyboard or via MIDI. The intention with Softube Vocoder is to provide an easy-to-use, limited but yet flexible vocoder within the UAD-2/Apollo framework.
The Softube Vocoder is an audio effect, designed to be controlled via a MIDI keyboard or by entering basic pitch information via the on-screen keyboard (and being able to transpose that via MIDI). Softube Vocoder listens to all MIDI channels at once (i.e. MIDI omni mode). The audio fed through the Vocoder will be interpreted to be the modulation signal while the carrier signal, the carrier synth sound source, is built into the plugin.
- Unvoiced
- Freeze section
- Output section
- Carrier synth
- Resynthesis control
This is the built in carrier sound source in Softube Vocoder. It is a six voice polyphonic synth that outputs one of four different waveform chosen for their rich harmonic spectra. The more overtones, the richer the output from the Vocoder will sound. The Waveforms are sawtooth, square wave, white noise and pulse wave with adjustable built in pulse width modulation. Each voice is controlled by an attack-hold-decay envelope and can also be pitch-modulated for additional vibrato.
The Carrier Synth can be controlled polyphonically via MIDI or be set to hold one or multiple notes in the Transpose Chord mode (where MIDI can be used for transposition of chords). When controlled via MIDI, it receives MIDI notes on all channels (omni mode).
The Resynthesis controls are the heart of the Softube Vocoder. This is where the user controls the levels of the separate bands of the bandpass filters that synthesize the speech. All bands also have common controls for emphasis (resonance) and shape of their envelope followers.
The unvoiced section of the Softube Vocoder reacts to, and synthesizes high frequency plosive sounds such as “s”, “t”, “r”, “th” and similar sounds. The sensitivity knob controls the behavior of the high frequency filter and gate, while the volume knob sets the mix level of the synthesized noise that replaces the unvoiced parts in your speech.
The Freeze section lets the user capture a particular syllable or vocal formant in the resynthesis filters and hold it. This can be done via MIDI or in sync with your DAW (every bar, 1/2 bar, 1/4th note, 8th note or 16th note).
The Output section features controls of the stereo width, wet/dry mix and overall output volume.
Unvoiced Sensitivity: This knob controls the gate level of the high frequency detector for the unvoiced part. Adjust this knob in order to optimize the perfect transmission of plosive sounds such as “s”, “t”, “th” and similar.
Unvoiced Volume: This control sets the volume mix level of the noise source that is substituting the high frequency in sound and unvoiced plosives in speech.
Freeze: The Freeze function makes the Vocoder “sample” the current frequency state of the analysis filters. This can be done manually (ON), via external midi note on (MIDI) or automatically clocked by the DAW tempo (1 bar / 1/2 bar / 1/4 bar / 1/8 bar / 1/16 bar).
Note: A saved preset with this function used to “capture” a formant via ON only will recall the “capturing behaviour” not the resulting formant.
Stereo Width: This knob sets the amount of spread between the even and odd bands. Odd bands are panned right and even bands left to the extremes when this knob is turned fully clockwise.
Note: When using the mono version of the plugin, increasing the stereo width will have the side-effect that only even band will be heard.
Parallel Blend: This knob controls the output mix balance between the wet, vocoded signal, and a representation of the dry, unaffected signal input. Use this knob to blend in some portion of your original signal with the vocoded signal.
Output Volume: This is the overall output volume knob. Use this to increase or reduce output volume if desired or if sharp transients that might occur with high emphasis values clip the output.
Master Tune: The Master Tune knob controls the nominal pitch of the built-in carrier synth. With this knob at 12 o'clock, the carrier synth is tuned to a standard 440Hz for A4. Fully counter-clockwise the pitch can be lowered 2 semitones and fully clockwise raised 2 semitones.
Carrier Octave: This set of buttons controls the octave register in which the notes entered on the keyboard in Transpose Chord Mode are played.
Carrier Attack: The Carrier Attack knob controls the attack/raise time in which the carrier synth responds when controlled over MIDI. The further clockwise this knob is set, the longer attack time. Fully clockwise, attack time will be approximately 4 seconds.
Carrier Decay: The Carrier Decay knob controls the decay/fall time in which the carrier synth responds when controlled over MIDI. The longer decay time, the longer the carrier synth notes will linger when a key on your MIDI control keyboard is released (whether this is heard or not depends of course on the input modulator signal). When this knob is set at fully clockwise, decay time will be approximately 4 seconds.
Carrier Waveform: These buttons set the carrier synth waveform used, all of which are chosen for their harmonic-rich properties. The top one, the sawtooth shape contains all harmonic overtones, while the square wave only contain odd overtones in its harmonic spectra. The noise waveform contain all frequencies and is inharmonic by its nature. It works great as carrier for rhythmic content that is intended to remain inharmonic.
The bottom waveform is a bit special. It is a narrow pulse wave with its pulse width modulated by a built in modulation. This modulation amount can be set by the PWM knob (see description below).
Resynthesis Control: The Resynthesis window shows all active bands and their response to the input signal in the vocoder. It also act as volume control for each band. Click on a band and drag up or down to increase or decrease the relative volume level of that band.
The number of bands currently active will each be reflected in the Resynthesis Control window by a moving meter (except when freeze is engaged, see below). If fewer bands than 20 are selected via the Bands select buttons, only bands that are activated will have moving meters present.
Pitch Modulation: This knob sets the amount of fast pitch-modulation on the carrier synth, also called vibrato.
Transpose Chord Mode: Transpose Chord Mode is activated by default. Transpose chord activates the on-screen keyboard where pitch can be entered to form the basis of the carrier synth sound. When midi information is entered above C3, the chord entered via on screen keyboard will be transposed accordingly. This means that the lowest note in that chord will be the root so that, for example, a C-minor chord (C-Ds-G) transposed by a E3 will play a E-minor chord, while a E-minor chord (E-G-B) transposed by the same offset, E3, will play a Gs-minor.
Softube Vocoder uses last midi note high priority, which means that a MIDI note played after another takes priority if it is higher in pitch.
Keyboard C to B: This is where the you enter the pitch information for the Transpose Chord Mode. When more than six keys are entered, adding more keys will start to “cross out” the old keys indicating voices being stolen. This is due to the six voice limitation.
Carrier PWM: The bottom waveform that can be selected by the Carrier Waveform buttons described above is a pulse wave. PWM is short for Pulse Width Modulation and this pulse wave's width is being swiftly modulated by an built in modulation. This knob sets the amount of this modulation.
Emphasis: Emphasis is how steep the response of each band in the Resynthesis part is. Increasing this knob makes the vocoder sound more hollow and “cold”.
Spectral Tilt: This knob is for swiftly setting the spectral weight of the vocoder output. The Spectral Tilt knob goes from weight on low frequency bands at counter-clockwise to flat at 12 o'clock, to spectral weight on high frequency bands at fully clockwise.
Shape: This is the envelope control of the Resynthesis part. At fully counter-clockwise, the attack and decay both stay fairly short, while increasing this knob to fully clockwise gives a much longer response with an added “sloppy” effect. Great for vintage vocoding sounds!
Bands: This is the number of bands currently in use. The Bands buttons selects between 4,8,12,16 or 20 bands. Generally speaking, the more bands used, the easier it is to hear the vocal message conveyed through the vocoder.
The Softube Vocoder has been developed with a quite basic feature-set, but still with enough controls to make it flexible enough to cover all your vocoding needs.
1. Use fewer bands for a more crude, vintage robotic sounding vocoder.
2. Make use of the DAW synced freeze function for creating fun and inspiring textures.
3. Add the vocoder to process rhythmic material in order to create interesting textures in your slow synth-pads.
4. Use a vocoded noise mix with high emphasis to create a kind of tuned “pseudo-reverb”.
A handy feature when adjusting the bands in the Resynthesis window is the ability to link and adjust all bands at once. Simply press and hold down the shift-button while clicking on and adjusting a band to adjust them all!
A whole range of added control can be accessed with Extended Features. Please see the separate "Extended Features" manual for more information.
Jacopo Lovatello – Modeling
Björn Rödseth – Mentoring, modeling
Kristofer Ulfves – Product owner, user manual, testing, presets
Maxus Widarson, Markus Krona, and Todd Urban – Testing
Niklas Odelholm – Graphic design
Ulf Ekelöf – 3D rendering