Originally published in Electronic Musician August 1,2003 -- by Dennis Miller

4ormulator Vocoder Extreme Basic 3.1 (Win, $49)

Vocoders are all the rage these days, but Richard Wolton has created a vocoder with a difference. Unlike most other vocoders, 4ormulator offers a wide range of options for configuring and modulating the bandpass filters that are used to analyze the input source sound, and unique ways to configure the bank of filters that is used to create the output. You can employ up to 260 filters in a bank, “tune” them to any equal-tempered interval, and modify their center frequencies using an LFO with adjustable rate and depth. Though you can't save your own custom settings in the unregistered version, its 32 presets provide a wide variety of sound-shaping options that can do wonders to whatever audio is on the track to which you apply this VST or DX plug-in. And, of course, you can record the output of any patch you make directly in your host software.

FIG. 5: 4ormulator is a powerful vocoder that offers a unique approach to configuring its two filter banks. The Edit window (right) is where you set the frequencies for the filters.

4ormulator's interface is split into two screens (see Fig. 5). The opening screen is where you'll find knobs and sliders for adjusting parameters such as volume, wet/dry mix, and global coarse and fine pitch (no increments are shown on the sliders). There's a Glide control for adjusting the time it takes for a change to the Pitch parameter to kick in; a very high setting can produce beautiful, cascading sounds. You can also pick from among the 32 presets by clicking on the Effects Selector, which is a dial-like interface. As you hold the mouse button down and move around the dial, the different preset numbers appear. Release the mouse when the number you want is showing, and it will be loaded.

The second work window is the Editor, which is where the fun really begins. Among the screenful of controls are areas for adjusting the two bandpass-filter banks. Filter 1 represents the bank of filters that is used to extract spectral information from your source sound, and filter 2 is the bank that modifies the carrier signal that will pass through it, under the control of the data derived by filter 1. Though you can set the center frequencies of the bandpass filters only in half-step increments, you can apply a global fine-tuning parameter for more exact control.

The large keyboard in the middle of the screen is used to determine how many filters will be used by filter 2. Filter banks in 4ormulator are made up of sets of filters whose frequencies are “harmonically” related; that is, their frequencies are whole-number multiples of the base frequency. By enabling a note on the onscreen keyboard, you define a fundamental frequency for a set of filters, and you then specify how many additional filters will be in that set by clicking on one or more of the buttons (marked H) found under the keyboard. Here again there are a total of 260 filters, and you can employ them “dynamically” — 10 sets with 26 filters each, 20 sets with 13 filters each, and so on.

The filter-tuning system is unique and takes a bit of getting used to, but the power it provides for creating unusual effects is huge. For example, you can take a song in a major key and jam it through a bank of filters tuned in a minor key; the results can be quite surprising. Unfortunately, you can't automate the controls using MIDI Control Change messages; that would be a useful enhancement for a future release.

Using a looping drum track as a carrier, I got interesting results with nearly all the presets. Preset 11 was especially tasty, with its delicate ringing quality, as was preset 17, with its sweeping-frequency effect. Number 14 conjured up some serious dissonance. Several presets produced a variety of resonator and comb-filter effects, while others offered varying amounts of distortion.

This is one “demo” that packs a punch, and I would recommend that you give it a serious look.