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Section 0

Fact Sheet

These pages have cropped up a few times over the years, usually named "Chroma fact sheet" and sometimes in conjunction with the Product Brochure. Their origin is unknown.

Interestingly, a number of parameters are different than what we've seen on production units; obviously numerous changes were made between ARP and CBS/Fender. The following table outlines the differences.

  Fact Sheet Production
# Section Parameter Section Parameter
1 Control Patch Control Patch
2   Keyboard Algorithm   Footswitch Mode (Poly/Mono on first fifty)
3   Bend Range   Keyboard Algorithm
7 Glide Mode Glide Shape
8 Sweep Rate Sweep Mode
9   Rate Track   Rate
10   Mode   Rate Mod
12   Amplitude Control   Amplitude Mod
14 Envelope 1 Rate Touch Envelope 1 Attack
15   Attack   Attack Mod
17   Decay Track   Decay Mod
21 Envelope 2 Rate Touch Envelope 2 Attack
22   Attack   Attack Mod
24   Decay Track   Decay Mod
27 Pitch Bend On/Off Pitch Mod 1 Select
28   Mod 1 Select   Mod 1 Depth
29   Mod 1 Depth   Mod 2 Select
30   Mod 2 Select   Mod 2 Depth
31   Mod 2 Depth   Mod 3 Select
32 Wave Shape Wave Shape   Mod 3 Depth
33   Width Wave Shape Wave Shape
34   Mod Select   Width
35   Mod Depth   Mod Select
36 Filter LP/HP   Mod Depth
37   Resonance Cutoff LP/HP
38   Tune   Resonance
39   Tune Track   Tune

Text Transcription

Page 1

This text appears at the top of the page, apparently added with a typewriter after the pages were printed: "NOTE: New information plus photo on Chroma should be available in a month or so. Will send."

The ARP Chroma brings to the world of programmable polyphonic synthesizers a level of expression and control never before available. More important, the Chroma is a practical live performance instrument, and a computer-based musical system which can grow with its owner.

The Chroma's keyboard is touch responsive. A separate microprocessor is used to scan the 64-note wooden piano keyboard to capture the key velocity both on depression and on key release. The key velocity can be used to affect such parameters as volume, brilliance, pulse width, and many other functions. Since the keyboard is computer controlled, parameters such as the degree of sensitivity, channel assignment sequence, and tracking are all variable.

The Chroma utilizes the most recent microprocessor technology to create a software based musical instrument. There are two microprocessor systems in the instrument; one just for scanning the keyboard, and one to control the audio synthesis. Unlike other polyphonic synthesizers, the Chroma generates all control signals directly in real time. Functions such as envelope generation, modulation, and signal selection are all computer generated and controlled.

There are 16 synthesizer channels, each employing a digitally controlled analog oscillator, filter, and amplifier. Channels may be paired and patched for two or four pole filter operation, ring modulator and sync effects. A noise generator is also routed to each of the channels. All channels are capable of being independently programmed, thus permitting many different sounds and textures to be played at the same time.

The Chroma can store up to 50 different programs, each directly accessible from the front panel. Each program stores all of the information needed to entirely set up the instrument, including keyboard split locations, transpositions, detunings, effects pedals, keyboard response and more. The programs are maintained by a battery backup system when the power is off. For more flexibility, there is a cassette interface built in to the instrument, allowing you to store programs on ordinary recording cassettes and retrieve them later.

When editing or creating a new program, the 50 program select switches become parameter select switches for the synthesizer channels. All parameters such as waveform select, filter tuning, envelope shape, keyboard sensitivity, etc., can then be accessed and modified while playing the instrument.

A program link function is also provided which permits two programs to be called at the same time, either in unison, or across a keyboard split.

The Chroma is also equipped with a computer interface jack which allows the instrument to be connected to an external computer. All keyboard and program information is accessible through this connection. With proper software, a computer will be capable of playing or programming the instrument. Since the Chroma is software based, it can become a "music terminal" for a computer system.

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Envelope 1

Envelope 2