CAMEL AUDIO Cameleon 1.3 (Mac/Win)

Morphing, spectral analysis, and additive synthesis in one tidy package.
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FIG. 1: Camel Audio Cameleon''s additive-synthesis panel lets you control the individual harmonics for additive synthesis (upper window) as well as the spectral characteristics of the noise component of the sound (lower window). Each breakpoint in the additive region has its own harmonic spectrum, and the harmonic and noise spectra can be analyzed from audio files.

As the name implies, Camel Audio's Cameleon synthesizer plug-in is able to change color at will to suit its surroundings. It manifests its chameleon-like character in two ways: by morphing among four voices and by analyzing audio and graphics files for resynthesis. Cameleon offers you control of the finest details of additive synthesis, but also lets you do a lot of creative synthesis without getting mired in those details. For instant gratification, Cameleon comes with an extensive preset library and offers several varieties of preset randomizing.

Cameleon is available as a VST plug-in for Windows as well as Mac OS 9 and OS X, and as an AU plug-in for Mac OS X. At its heart, Cameleon is an additive synth, and like all additive synths, is CPU hungry. Several voices of a complex, morphing preset loaded with effects will tax even the heftiest CPU, but a number of useful CPU usage tips are included in the manual. I tested both the AU and VST versions in several hosts on a Mac dual G5/2.0 GHz desktop as well as a G4/800 MHz laptop and was able to make good use of Cameleon even on the laptop.

Cameleon's implementation of additive synthesis is both powerful and a bit unusual. I'll begin with a look at that, then get into morphing, analysis-resynthesis, effects, and automation.


Additive synthesis, of which the drawbar organ is the best know example, constructs complex sounds by controlling the level of individual sine-wave components. (Any periodic sound can be analyzed and resynthesized as a combination of sine-wave components at different amplitude levels.) Cameleon allows you to easily manipulate harmonically related sine-wave components to produce pitched sounds, and it also allows you to individually “detune” those components to produce clangorous, inharmonic timbres (see Fig. 1).

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FIG. 2: The corners of Morph Square represent Cameleon''s four voices. The dot-and-line graphic within the square represents the morphing pattern among the four voices. The Morph Timeline at the top shows the horizontal (Morph X) or vertical (Morph Y) morphing pattern over time.

Another feature of natural sounds, and one whose absence gives organs their distinctive character, is that their spectrum changes over time. If you loop short slices of a single piano note, for example, those taken near the beginning of the note will sound different from those taken near the end. Cameleon handles that issue with breakpoint envelopes that allow you to control both the level and harmonic content at as many as 128 different points in time.

Needless to say, having to manage the levels of 64 sine waves at 128 different points in time is a tedious process, and fortunately, nothing that time consuming is usually required. In addition to offering a variety of standard waveforms as starting points and providing global tools for manipulating their harmonics, Cameleon can extract the evolving harmonic content from any recorded sound and, in an interesting twist, also from any graphics file (.bmp only), by interpreting it as a sonogram.

Spectral analysis and resynthesis is, of course, not new to Cameleon, but Cameleon's approach sets it apart in two ways. First, it attempts to separate a sound's pitched and nonpitched components, resynthesizing the latter using noise with breakpoint-enveloped multiband filtering. That dramatically expands Cameleon's sound palette, making it an excellent tool for percussion as well as speech resynthesis. Web Clip 1 is an example of the latter.

The second way Cameleon differs from typical additive synths is that it allows you to map different sounds across key and Velocity zones, as is commonly done in sample players. The limitation to eight key zones seemed a little stingy to me at first. When I realized, however, that this is not multisampling, in which a single sample doesn't transpose well over large ranges, but is rather a form of crossfade synthesis, I found it quite a powerful feature.


Like analysis-resynthesis, morphing among different voices is not a new technique, but again, Cameleon's implementation ventures off the beaten path. The Morph space consists of a square, the corners of which represent different voices (see Fig. 2). By default, a single white dot represents the morph position relative to the four presets, and you can move the dot around with the mouse to achieve different morphings.

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FIG. 3: Cameleon''s Effects panel offers standard distortion, chorus, stereo delay, and reverb as well as multiband and formant filtering. The formant filter''s spectrum is controlled with a breakpoint display (top) offering as many as 128 breakpoints.

Behind the scenes, moving the white dot is actually morphing among the amplitude envelopes, harmonic spectra, and noise envelopes of the four presets. In Cameleon, you can choose to morph those characteristics separately, in which case the white-dot color separates into green, red, and blue dots representing the individual characteristics. You can, for example, choose the amplitude envelope from one voice, the harmonic spectrum from another, and the noise envelope from a third. And you can assign different MIDI controllers to each dimension of each characteristic, giving you what amounts to six-dimension, real-time control of the morphing process.

Morphing can also be automated directly in Cameleon using breakpoint envelopes on what is called the Morph Timeline. Separate Timeline envelopes control morphing in the horizontal and vertical dimensions of the square. Morphing automation is available only for combined (white-dot) morphing, but that is quite powerful in itself. A good collection of morph-automation presets is provided, and morphing can be randomized separately from the rest of the parameters.

Cameleon's randomization options are extensive. Clicking the Random button at the top right of the control panel, just under the preset selector, randomly selects presets for each of the voices of the Morph Square. Usually the presets are selected from the currently active preset category, but occasionally a preset from another category will be selected, and in that case, the preset's parameters will be adjusted in a way appropriate for the active category. For example, if you've selected the Basses category then click the Random button, you will either get a bass preset for each voice or a nonbass preset adjusted to bass characteristics. The Random button also randomizes the settings on the Morph, Easy, and Effects panels. (The settings on those panels can also be randomized individually.) The result is that you always get a useful sound in the desired category. Web Clip 2 is a three-part example made totally from random presets.


Cameleon's Effects panel includes the obligatory complement of effects — distortion, chorus, stereo delay, and reverb — as well as a resonant multimode filter and a formant filter (see Fig. 3). It might seem odd to have the filters in the effects section, but remember this is additive synthesis, and filters are not part of the basic voice structure.

With the exception of the formant filter, the effects are basic, with three or four controls each. Distortion has harmonic distortion, tube-emulating overdrive, bass enhancement, and a simple compressor. The stereo delay has separate delay times for the left and right channels, but the delays are always synced to tempo. Randomization applies to all effects parameters including whether the effect is on or off. Randomizing does not currently affect the formant filter, but that is planned for a future release.

The formant filter is the most interesting Cameleon effect and comes with 15 presets to get you started. Like the envelopes, you set up the formant filter by creating and moving breakpoints, with the horizontal position indicating frequency and the vertical position controlling cut or boost. Also like the envelopes, you can have as many as 128 breakpoints. The frequency range is 20 Hz to 20 kHz. You can shift the entire filter spectrum up or down in frequency using MIDI or one of Cameleon's built-in modulators.

Cameleon's Mod panel allows you to map eight modulation sources to eight targets, with individual range settings for each mapping. Sources have two LFOs and a breakpoint envelope as well as most MIDI messages, with note number and Velocity. Modulation targets have the individual Morph Square dimensions and most effects parameters. You can also use Cameleon's MIDI Learn function to directly assign any MIDI controller to any knob, button, or numerical control.

The LFOs are rather basic, with sine, saw, and square waveforms and, like the delay times, must always be synced to tempo. The LFO rate ranges from eight measures to one eighth note. The breakpoint envelope is a welcome addition. Its routing is somewhat limited, but includes most of Cameleon's morphing and filter parameters.

Cameleon's Easy panel is used for global settings such as maximum number of voices and maximum number of harmonics (useful for saving CPU), output mix of the harmonic and noise-based components of the sound, a dedicated LFO for vibrato and tremolo, and a dedicated output-amplitude envelope. The envelope has a Loop button, which turns on looping for the harmonic and noise components of each of Cameleon's four voices. It also features a useful Stretch control for stretching or shrinking the harmonic and noise breakpoint envelopes of each voice.

Cameleon takes an interesting approach to additive synthesis, and its ability to analyze and resynthesize audio or graphics files as well as to morph among four voices greatly increases its reach. With all that flexibility, it's almost a no-brainer to come up with original sounds. Finally, the extensive preset library and the well-written manual help make this complex synth quickly accessible. Whether additive synthesis appeals to you or not, you owe it to yourself to download the demo from Camel Audio's Web site,, to try it out.

Len Sassois an associate editor of EM. He can be contacted through his Web site

Minimum System Requirements

Cameleon 1.3

MAC: G4/400 MHz; 128 MB RAM; Mac OS 9/OS X

PC: Pentium III/600 GHz; 128 MB RAM; Windows 98/XP


Camel Audio

Cameleon 1.3 (Mac/Win)
analysis-resynthesis additive
synthesizer plug-in



PROS: Excellent and unusual sounding. Extensive preset library and randomization options. Morphing and analysis-resynthesis greatly expand sound palette.

CONS: LFOs and delay times always synced to tempo. Breakpoint editing can be touchy.


Camel Audio