Tim's Atari MIDI World

AEX: Tangerine Dream Machine Version 2!


[Screen-shot: AEX main screen]

In MyAtari's March 2002 edition (see link section), I reviewed Dr Ambient's program called AEX, the Tangerine Dream Machine. I have had the pleasure of being beta tester, in which we have now completed version 2, which has major updates from version 1. The updates include two voices as well as a percussion voice. This makes this program resemble and sound like popular PC programs such as Rebirth, however with many more variations as well as real-time elements in place. I had a hand in the programming as well as I got to program drum patterns and articulations for voice 2 within the source code (using GFA BASIC).

AEX v2 runs on the ST (640x400x2) and on the Falcon (640x480x2/16/256). The TT is not yet supported, although you can still run it in ST high resolution mode. TT medium resolution is dependent on the color scheme set in the TT VDI itself (Color CPX), so the colors will look rather psychotic!

There are no longer three separate programs, only one containing all resolutions. AEX is a keyboard-driven program. There is no mouse support. However, this enables AEX to become a real-time performance instrument once you become familiar with scrolling around the AEX screen.

For Falcon owners, a newly designed AEX logo as well as the three Tangerines in the corner makes using AEX a real treat. This new version has many more improvements as well as excellent graphics making full use of the Falcon's color spectrum. I am sure that Edgar Froese would be using it himself if he still used Atari (perhaps they will someday!).

New in version 2.0
48 algorithms. There are new arpeggio-style algorithms (1-24) for this new version of AEX. They sound quite nice as well! These are accessed using the [(] and [)] keys on the numeric keypad. It is called the AEX index.

In the global menu:

  • Two voices and a percussion voice. Selectable algorithms for voice 2 and percussion. Muting of each voice using A.E.X on the computer keyboard (A=voice 1, E=voice 2, X=drums).
  • Real-time immediate transpose 0-12 semitones, using keys [Esc], [1] to [0] and [+], which brings the key up a full octave.
  • Copying patterns to function keys. Another major update. Works like a snap-shot function of all parameters.
  • Help screen implemented: by pressing the [Help] key, you scroll through the keyboard commands.

Inside AEX
When first opening AEX, you can see the screens are divided into five main groups. By using the numeric keypad of the computer keyboard you can access these screens. A matter of point here: AEX is keyboard-driven, which means there are no mouse actions available. However, this makes for more of a real-time system as you go quickly between screens and parameters and change them on the fly while AEX is running. Here are the main keyboard commands:

Numeric keypad

  • [1] Pattern screen
  • [2] Modulator screen
  • [3] Logic screen
  • [4] Scale screen
  • [5] Global screen
  • [(], [)] and [/] toggle through the AEX index, which creates variations in the sequence
  • [+] and [-] scroll through the parameters to make changes 

Main keyboard

  • [Caps Lock] starts sequence
  • Space bar stops sequence
  • [L] loads pattern
  • [S] saves pattern (remember to put in .AEX as an extension in order to save it correctly)
  • [Backspace] exits program
  • Arrow keys scroll through the screen options (or cells) going from icon to icon or cell to cell in the Pattern screen
  • Transpose (0-12 semitones), using keys [Esc], [1] to [0] and [+], which brings the key up a full octave

Using AEX
Hit [Caps lock] to start AEX. Now hit [4]. You are now on the scale screen. Using the [+] and [-] keys, change F_5 to C_4. Hit [Enter] (not [Return]) to transact the change. Now using the [(] and [)] keys, change the AEX index to 9. Hit [Enter]. You will hear a change within the sequence. Now play with the AEX index a bit and change it to 1, then 2, then 3 and so on, hitting [Enter] as you go. You will hear changes within the sequence as it is running. This is very much a real-time feature.

Hit [5] which brings you to the global screen. Using the arrow keys scroll to voice 1 parameters and change the sound (patch) which is the second icon. Go over 4 icons to the Sub-voice icon and change it to 5 (using the [+] and [-] keys) thus making fifths). Go to the next icon where you can take AEX into or out of random mode. The next icon toggles the "conductor". With the conductor off, AEX makes a constant rhythm. However, to make variations, keep the conductor to on (001).

The next row starts with a global icon for Tempo or BPM (Beats Per Minute). Slowing down AEX creates different feels in the music. The next set of icons is for the second voice. This includes MIDI channel, voice (patch change), volume and algorithms that change the rhythm articulations of voice 2. The next set are the drum parameters. Voice (patch change) allows you to change drum kits, providing your module provides this function. The next icon is volume, and the last are algorithms for drum patterns. Changing these while the music is playing can create variation in the drums. These patterns are built into AEX and cannot be edited (yet). Try muting each voice using the keys: A.E.X on the computer keyboard (A=voice 1, E=voice 2, X=drums). This is very much a real-time feature.

What follows now is a description of the icons and their uses.

The pattern screen
The parameters in this screen can all be changed by hand (by going from parameter to parameter with the arrow keys), so this is one way you can use AEX. However, AEX is also set up to intelligently change these settings in an automatic fashion with many variations. Parameters for change include:

  • Key: the actual notes
  • Vel (velocity): the volume of each note
  • Pan: the stereo placement of each note
  • CC1: an assignable continuous controller message
  • CC2: another assignable continuous controller message. You can assign them on the Global screen (see below)

The modulator
[2] on the numeric keypad - makes up a simple AR envelope generator, with five possible destinations. Icons (from left to right):

  • Initial (start) level (0-127)
  • Attack time (0-32)
  • Attack level (0-127)
  • Release level (0-127)
  • Destination (1-5, where 1=key, 2=velocity, 3=panorama, 4=CC1, 5=CC2)

Note: CC1 and CC2 are freely assignable controllers, the controller type can be set in the Global menu. In the DEF.AEX file they are set to 74 and 71 (XG: cut-off frequency and resonance).

The logic menu
[3] on the numeric keypad - a simulation of an LFO (Low Frequency Oscillator), which has also five possible destinations. There are also differences, compared to a "normal" LFO: a value of zero means no operation, a value of 1 will affect every single entry, and a value of 2 will affect two successive entries, and so on. Icons (from left to right):

  • Random
  • Reverse
  • Zero
  • Rotate
  • Destination (1-5, same as the modulator)

The scale menu
[4] on the numeric keypad - here is where the actual sequence is generated. There are 32 algorithms available. These can be selected by pressing the [(], [)] and [/] keys on the numeric keypad:

  • [(] Value down
  • [)] Value up
  • [/] Random value
  • Icon assignment: 1-5 for the actual "scale"

Note: as calculations work from left to right, the first icon will in general reflect the lowest note produced.

The global menu
[5] on the numeric keypad

Upper row:

Voice 1

  • MIDI channel (1-16)
  • Program change (0-127)
  • Volume (0-127)
  • CC1 (0-127)
  • CC2 (0-127)
  • Sub-voice (0-24 semitones)
  • Random playback (0=Off, 1=On)
  • Conductor: (0=Off, 1=On)

Note: Random will pick random note values from the "key" column, instead of playing them one after another. The Conductor mode looks if successive values in the key column are equal, and if so only the first will sound. If both random and conductor modes are switched on, AEX will keep "composing" new sequences every cycle.

Lower row:

Tempo BPM (0-127)

Voice 2

  • MIDI channel (1-16)
  • Program change (0-127)
  • Volume (0-127)
  • Algorithm (1-32) (changes the rhythm pattern of voice 2) programmed by Tim Conrardy


Note: Drums are transmitted on channel 10 by default.

  • Program change (0-127)
  • Volume (0-127)
  • Algorithm (1-64)These are built-in drum patterns: programmed by Tim Conrardy (2-22) and Jos Van De Gruiter (23-37) more are yet to come
  • Muting of each voice using the keys: A.E.X on the computer keyboard (A=voice 1, E=voice 2, X=drums)

Copy patterns to function keys
A new feature, here is how it works: Always make sure to be in the pattern screen! Position the cursor anywhere in the column you want to copy (like key, vel, pan, cc1, cc2). Press [C], then press a function key. In color mode the function keys already used are highlighted, the key that is used the last will have a box around it. This will be an excellent real-time feature once you build up and assign patterns to function keys. Simply pressing [F1] or [F5] will create instant changes to the music.

More on logic and modulation
These screens allow you to create more variations, which will affect whatever number is set in the last icon parameter (the arrow going right), which is called the "destination". Possible destinations are pulled from the Patterns screen:

  • Key (or note)
  • Velocity
  • Panorama (panning)
  • CC1
  • CC2

The best thing to do is experiment with these algorithms to see what happens to the music. Algorithms are represented by the graphs looking much like an oscilloscope. Remember that when you do a change, hit [Enter] to hear the change.

Use of CC1 and CC2
These are parameters settings to adjust controller messages. For example, XG synths use controllers 71 and 74 for filter frequency cut-off and resonance. In the Global menu, set CC1 to 71 and CC2 to 74 (icons 3 and 4, upper row). Then go to the Modulator by pressing [2] and set destination to 4 for CC1 or 5 for CC2.

The modulator parameters (icons 1 to 4) are:

  • Start value (0-127)
  • Attack time (0-32)
  • Attack value (0-127)
  • Release value (0-127)

This makes it possible to make nice filter sweeps without the hassle of changing all the values in the pattern editor. Of course, this also works for other destinations like pan and so on. Experiment!

In the Logic menu you can do similar things: try a value of 4 for random (first icon) and apply it to destination 4 or 5. This will emulate the classic sample and hold effect.

Creating rests
It is possible to insert rests:

  • In the Logic menu, third icon, destination 2 (velocity).
  • In the pattern editor, by setting velocity to zero.

Note values can be altered in a number of ways:

  • In the Scale/AEX menu (where destination is fixed)
  • In the Modulator menu (not as useful)
  • In the Logic menu, set destination to 1
  • In the pattern editor: by using the [+] and [-] keys

What's next?
While there is no official support for Atari computers, we are very thankful for people like Guido Goebertus for continuing to create quality programs for our platform. Guido is still continuing to code with a new program called ESEQ (Easy Sequencer). It will have many of the same features as AEX but with the ability to use multiple MIDI channels and more. Here is a screen-shot of the user interface. 

[Screen-shot: Easy Sequencer]

About Dr Ambient
Guido Goebertus (known as Dr Ambient) resides in the Netherlands where he is quietly working on his many projects which include Atari coding using GFA BASIC, graphic design using Terregan and Povray, and many music projects which include a CD called Songs of the High North: The project is all about the work of Robert W. Service, the famous "klondike poet" and the gold rush that took place in Alaska and the Yukon district between 1894 and 1898. His other project involves a huge collection (over 110 MB) of professional sounding Soundfonts for the SBLive!, including pads, synth sounds (sampled from the EMU Proteus 1 and 2, Yamaha Cs1x and Roland U-110), as well as some electric (Fender Strat) and acoustic guitars. Guido is also a faithful member of the Atari-MIDI forum at Yahoo as well as the moderator of the Atari-MIDI programmers forum.

[Image: AEX 2 tutorial]

A graphical tutorial of AEX.
[Click to enlarge]

News: ISEQ
There is a new version of Matucana's Grid Sequencer (reviewed in the November issue of MyAtari). He is now calling it ISEQ, and it will contain many unique "modules".

[Screen-shot: Grid Sequencer]

He has completed two: a new version of the Grid sequencer with many improvements. A new module called the Rogue Sequencer which simulates analog sequencers with lots of algorithmic twists. The third will be an alternate mouse controller inspired by Laurie Spiegel's Music Mouse. Download it below. Also please check out Matucana's home page.


  • AEX version 2
    A note for floppy-only users: For those with an ST floppy system only, you will need to delete a file from the AEX archive so it will fit on a 720 KB disk. The file to delete is AEXF256.DAT. This file only has to do with the 256-color version of AEX.
  • ISEQ by Matucana

Useful links


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MyAtari magazine - Feature #5, January 2003

Copyright 2003 MyAtari magazine