Mac VST and RTAS, PC VST Reviewed: PC VST versionThe vocoder has been around since 1939, when it was originally developed by Bell Labs for the encryption of speech for the military. Nowadays it's rather better known for novelty sounds like talking guitars, but it has many other musical applications, from ethereal pads to exotic drum loops. The vocoder works by splitting the frequency spectrum of the main 'modulator' audio signal into a number of bands, and using the levels of these bands to control the levels of frequency bands in a second, 'carrier' signal. Thus, the frequency content and dynamics of the modulator signal are imposed on the basic tonality of the carrier to provide the unique vocoder effect (for a more detailed explanation, see Gordon Reid's Synth Secrets from SOS July 2000).
Prosoniq's Orange Vocoder plug‑in uses 24 bands of filtering for detailed articulation, and adds a lot more functions besides. The graphics are, as you might expect, orange, and it's nice to see the most being made of a software interface, with easy‑to‑see knob pointers, text readout of parameter values, and a clearly laid‑out panel display. The Mixer panel at top left has three sliding level controls for Speech (modulator), Carrier, and the processed Filter output, while the Graphic Equaliser lets you click and drag a frequency response to define how the Speech input modulates the Carrier input. This works well, except that, unfortunately, changes don't take effect until you let go of the mouse.
Next is a Reverb section with Amount, Diffusion, and Decay faders. This uses the natural sustain of the Carrier sound to create reverb‑like decays which are very useful when turning short drum sounds into triggered drones, or to push the effected sound back in the mix compared to the direct one. The following Control section also has a filter bank Release dial, which provides a much simpler envelope release‑time effect. Also in this panel are Copy and Paste buttons to help when creating presets, and an Input Flip switch to swap the Carrier and Speech input signals.
So far, so good, but it's the next 'Use Synth' button that turns Orange Vocoder into something really special. Once this is activated, the Carrier no longer comes from an external input signal, but from the eight‑voice synthesizer in the panel beneath. Many musicians start out with good intentions when using a vocoder, but find it so tedious to route two suitable signals to it and then tweak them both for the desired effect that it ends up not being used very often. This time it's different since, using the Synth, you can have a host of ready‑to‑use presets to process any audio track within seconds.
The twin oscillators each have a four‑octave range with coarse and fine pitch controls, and a choice of Waves or Samples as the sound source. There are 10 different waveforms, each giving a different vocoded sound, plus an Off position, while the Waves option provides seven different sampled sounds including Vox, Strings, Airy, and Noise, which give the relevant qualities to the resulting sound. The two oscillators can be detuned or set to intervals just as on any other synth, but a neat two‑octave graphic keyboard lets you create up to eight‑note chords with them using the mouse, while an octave selector switch shifts these up and down for a total range of six octaves.
Other options in the Synth panel allow you to pitch‑modulate the oscillators using an LFO, the Modulator amplitude envelope, or its pitch envelope, while an associated Speed dial acts rather like the glide control on an analogue synth. Both oscillators are then passed through a variable Distortion section, and then finally through a 24dB/octave low‑pass filter with resonance. Sync and Ring Mod controls are also available to create further mayhem, along with a Master Tune dial. The sound range is impressive, from the standard talking instruments through to articulated synth chords, from clean ethereal voices through to dirt and grunge. You can turn drum loops into '1000 Flutes' or 'String Arpeggio', and complete tracks into 'Phat' synth sounds or 'Mosquito' effects.
Sadly, Orange Vocoder can't currently use MIDI notes to adjust the synth notes in real time, although I gather Prosoniq are working to make this possible in an update. In the meantime you could paste different chords into different presets and switch between them using program changes. Pronsoniq also claim that the vocoder isn't compatible with either Cubase 5.0 or Nuendo, although this is news to me, as I discovered this information after I successfully used it in Cubase 5.0.
There is a further disappointment for PC owners. Although the Mac version provides a second VocCarrier plug‑in to let you route separate stereo signals to both modulator and carrier, the PC version doesn't currently provide this option. The only way to use the Orange Vocoder in non‑synth mode is to make it a Master effect, when the left‑hand channel becomes the modulator, and the right one the carrier. I can't imagine many musicians wanting to process their entire track in this way, and all it would have taken to let PC owners have standard vocoding on individual tracks would be a switch to provide the same L/R mono vocoding inputs when used as a Send effect.
However, I suspect that most musicians will be using the Synth for the majority of processing, and used in this manner Orange Vocoder is a delight. Long‑term, it's crying out for the addition of VST 2.0 MIDI control to provide real‑time chord changes in sync with the music, but until then it provides more than enough to keep the majority of musicians happy. You can buy Orange Vocoder direct from the Prosoniq Plug‑In Shop on their web site. Martin Walker