I want my AEX!

Analog sequencers go to a new level

Atari-MIDI forum member Guido Goebertus (also known as Dr Ambient), has created an excellent application called AEX, which simulates in an intelligent fashion, the analog sequencers of yesteryear made famous by the works of Tangerine Dream, the exploratory electronic music group. I have had the pleasure of being beta tester, in which we completed a working "beta" version, now released to an unsuspecting Atari MIDI community. This is only the beginning as we have big plans for AEX. Some ideas for future versions include multiple AEX screens, some of which are configured for bass and percussion, making AEX a sort of Rebirth for Atari computers, but working through MIDI.

New Falcon version
Some big news however: the Dr has been working steadily on a new 256-color Falcon version, which is now ready for release! This new version has many more improvements as well as excellent graphics making full use of the Falcon's color spectrum. A polished metal look and stunning icons makes this application a real treat to use for Falcon owners. The icons are not for show however; each one has a different function. There are also more algorithms as well as a transpose feature (using the numerical keys), which makes changing keys a snap as well as striking. The same updates have been added to the ST mono version. See below for a MyAtari download! The zip contains both versions.

New in version 1.1

• 32 algorithms instead of 10
  These are accessed using the [(] and [)] keys on the numeric keypad. It is called the AEX index.
• In the global menu
  Random mode: this mode allows for more of an algorithmic feel to the sound.
  Conductor mode: puts in random rests, thus creating more interesting rhythms.
  Adjustable MIDI channel: allows you to set the MIDI channel for more control.
  XG controllers: XG is the Yamaha standard for GM, but brings it to a new level.
• Real time
  Transpose 0-12 semitones, using keys [Esc], [1] to [0] and [+], which brings the key up a full octave.

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] exit 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

1. Hit [Caps lock] to start AEX. Now hit [4]. You are now on the scale screen.
2. 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.
3. 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.

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):

1. Initial (start) level (0-127)
2. Attack time (0-32)
3. Attack level (0-127)
4. Release level (0-127)
5. 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: cutoff 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, abd a value of 2 will affect two successive entries, and so on. Icons (from left to right):

1. Random
2. Reverse
3. Zero
4. Rotate
5. 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

1. MIDI channel  (1-16)
2. Program change (0-127), Volume (0-127)
3. CC1 (0-127)
4. CC2 (0-127)
5. Sub-voice (0-24 semitones)
6. Random playback (0=Off, 1=On)
7. 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 (0-127)

XG controllers from left to right:
1: modulation depth
91: reverb depth
93: chorus depth
94: variation effect depth
73: attack time
72: release time
16: assign

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:

1. Key (or note)
2. Velocity
3. Panorama (panning)
4. CC1
5. 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 cutoff 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:

1. start value (0-127)
2. attack time (0-32)
3. attack value (0-127)
4. 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:

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

Note values can be altered in a number of ways:

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

I want my AEX
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. AEX sets an example of what can be done in this new century on a practical level as well as a creative one. Besides being a programmer, the Dr is an excellent musician, which is why his programs are well…so musical! Let every Atari musician exclaim, "I want my AEX!"
 

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MyAtari magazine - Feature #4, March 2002