This tutorial will discuss various in-depth aspect of Xx's Random Generators.

Step 1: Setting Up
 

• A. Open Xx's Track Mixer (double-click on any of the tracks in the Track Bar) and set up the first four tracks to use the Beatnik percussion instruments as shown here. 
  For more information about setting up Xx Tracks and using Beatnik or external MIDI devices, see Tutorial 1.
• B. Set Xx's tempo to 144 bpm and turn "Velocity" on as shown. 
  Turning "Velocity" on causes note colors to be used to indicate note velocities rather than the notes' track. You can see which colors correspond to which velocities by clicking at various points across the piano keyboard display and observing the color at the top of the keyboard display.
   
• C. Choose the "Modern1" scale with a root of "C", and select Poly mode as indicated below.
  
   
• D. Use the Bar Select Area at the bottom of the Xx window to select 4 bars.
   

Step 2: Using the Random Generator

• A. Open the Random Generator by selecting "Smart Random" from the Patterns menu. The Random Generator window will open up as shown here. 
  The Random Generator is used to generate sequences of notes within the selected area (4 bars in our example.) The window can be set to exercise some degree of control over the generated sequences. Here are some key points:
  • The Random Generator generates sequences on the selected track only.
  • Depending on the settings, the sequences can be completely random or completely controlled.
  • The Random Generator can vary pitch, velocity and rhythmic pattern in both predictable and random ways.
  • The Preview button plays exactly the sequence you will get by clicking the check mark.
  • Each time you click the Preview button, a different sequence will be generated. Hence, the same settings DO NOT produce the same results.
     
• B. Set the Random Generator values as shown here. 
   

   

  The settings in the top third of the window control how much pitch variation there will be as well as the basic unit of rhythm. In our case, there will be no variation in pitch (General Amplitude = 0 & Never repeat notes off). The basic unit is 16th notes (60 ticks).

  When Never repeat notes is turned on, successive notes of the same pitch are prohibited. This takes precedence over the General Amplitude setting. So if it were turned on here, there would be some variation in pitch even with General Amplitude = 0.

  The settings in the middle third of the window control the pattern and length of the rhythm loop. In our case, the loop is 16 beats and every other note will sound. This is the meaning of the string of note symbols and commas.
  The bottom third of the window controls how much the sequence is like a repeating loop. With Feedback set to 0% there is no looping--the whole sequence is random. With Feedback set to 100%, the sequence loops in a way controlled by the "loop a" and "loop b" settings. Other Feedback values produce results in-between--some looping mixed with some randomness.
   

• C. Click the check mark and the Random Generator will generate a 4 bar sequence of alternating 16th notes and rests much like that shown here. 
  The notes in the sequence vary in velocity but are all the same pitch. You have no control over the velocity variations except as they are influenced by the Feedback and loop settings. You can, of course, use Xx's other tools to edit the velocities later.

  Delete the sequence.
   

• D. Select 8 bars this time and open the Random Generator again.
  Change the General Amplitude, Never repeat notes and Rhythmic Pattern values as shown below then click the green check mark to generate the sequence. 
  Since the Random Generator generates different sequences each time it is applied, there is no way to picture exactly what you'll get, but here is an example.
  Here are three things to notice:
  • The sequence appears not to loop--each group of 16 beats is different. This is a result of the Feedback setting of 0%.
  • The pitch range is limited to roughly an octave. This results from the General Amplitude setting of 30. (The range is 0 to 200.)
  • The rhythmic pattern exactly matches the pattern shown in the Random Generator window.

  
  Delete the sequence.

   
• E. With 8 bars still selected, open the Random Generator again.
  Change the Frequency to 100% either by moving the slider or clicking the number at its right end and typing in "100". Now click the green check mark to generate another sequence.
  Notice this time that the sequence repeats itself every measure. The frequency setting of 100% ensures that the sequence eventually repeats. If the frequency were high but less than 100% the successive measures would be similar but not exact replicas. As we saw above, if the frequency is low (0% in that case) the successive measures are very different (i.e. more random).
  The length of the repeating pattern is determined by the "loop a" and "loop b" settings. Their interaction is complex, but here are a few guidelines.
   
  • Keep the loop a setting less than the loop b setting.
  • Set loop b to half the size of the loop you want.
  • If the Rhythm Pattern is irregular and you want it repeated, make both loop a and loop b multiples of the Rhythm Pattern length. 
    (Note that in our example, the pattern does not repeat because loop a is 8 while the pattern length is 16.)

  Delete the sequence.

   
• F. With 8 bars still selected, open the Random Generator again.
  Change loop a to 12 by either using the scroll "wedges" or by clicking the number and typing "12". Now click the green check mark to generate another sequence. 
  The main thing to notice about this sequence is that the rhythm pattern DOES NOT repeat every measure. It does, however, repeat every 2 measures. This is forced by the frequency setting of 100% together with the loop b setting of 16.

  Delete the sequence.
   

• G. This time, select 32 measures, and open the Random Generator again.
  Change the frequency to 90%, change loop a to 24, and change loop b to 64. Click the green check mark to generate another sequence.
  One thing to notice about this sequence is that groups of 3 measures (48 16th notes) are similar though not identical. The loop a setting of 24 accounts for the 3 measure pattern and the frequency of 90% accounts for the variation between successive 3 measure groups.
   
• H. With the same 32 measures still selected, choose track 2 by clicking the pink square in the Track Selector Bar.
  Open the Random Generator and change the Start Duration to 120 and the loop a setting to 32. Click the green check mark to generate a second track.
  Choose track 3, open the Random Generator again and change some of the other settings. In particular, make some changes to the Rhythmic Pattern. Click the green check mark to generate a third track.
  Of course, your results will differ, but here's an example of what might result.
  Delete all tracks.
   
• I. Select track 10 by clicking the red square in the Track Selector Bar. (If you are using Beatnik, track 10 will use percussion sounds. If you are using an external MIDI device, you will need to set MIDI channel 10 to a percussion program. This is the standard setting for GM devices.)
  Change Xx's scale mode to "Dodecaphonic" and turn track 10's Track Loop Switch on.
  Open the Random Generator and change its settings as shown.
  The Start Duration of 80 ticks means the rhythm pattern units will be 8th note triplets. The General Amplitude and "Never repeat notes" settings ensure that each use of the Random Generator will (usually) result in notes of the same pitch. The Rhythmic Pattern shown is one measure of quarter notes. (The rests are the remaining 8th note triplets.)

  Select 4 bars and experiment with various Frequency, loop a and loop b settings. For this experiment, it's a good idea to choose high frequencies and use odd numbers for the loop settings (like loop a = 5 and loop b = 11, for example).

  Each time you click the green check mark, make sure the newly added notes are selected, and use the up and down arrow keys to change the percussion sound while the sequence is playing. Note that you can select all notes of a specific pitch by clicking on that pitch on the keyboard at the left. (Sometimes the Random Generator may produce two pitches. If this happens, you can select one of the pitches and move the notes to match the other. This way, each pass corresponds to a new percussion sound.)

  If you set Xx's grid to 80 to match the Random Generator's Start Duration, you can conveniently use the right and left arrow keys to nudge some percussion parts forward or backward by 8th note triplets. If you hold down the Control key while doing this, the notes will wrap around the other end.
  The illustration shows one example of a percussion track generated this way.

Step 3: Using the MultiTrack Random Generator
In the previous section, we saw how to generate random patterns using the Random Generator. In examples G and H, we generated multi-track random sequences by using the Random Generator several times in a row.
The MultiTrack Random Generator is designed to generate several tracks at once (8 maximum) and it behaves a little differently than the Random Generator. One of the major differences is that there are no "Frequency" and "loop" settings. So early parts of the sequence can't be made to influence the later parts. On the other hand, the MultiTrack Random Generator gives you more control over pitch.
 

• A. Delete all tracks or open a new Xx window.
  It's also a good idea to select a scale mode (rather than "Dodecaphonic") as the MultiTrack Random Generator produces thick clusters on notes.
   
• B. Open the MultiTrack Random Generator by selecting "Multi Track Random" from the Patterns menu. The window shown below will open. 
  As with the Random Generator, you need to select a bar range for the MultiTrack Random Generator before opening the window.
   
• C. Select the number of tracks you want to generate. Note that the track selected when you open the MultiTrack Random Generator will be the first track and successive tracks will be used, up to the number chosen.
   
• D. Set "Pitch range", "Frequency" and "Preferred intervals" as shown.
  The red sliders are used to change these settings. Click and drag to the right to increase the values.
  The Pitch range setting is similar to the "General Amplitude" setting in the Random Generator. It controls how wide a range the generated notes will fall into.
  The Frequency setting has to do with how rapidly and radically the pitches change. It has nothing to do with frequency in the sense of the Random Generator.
  The Preferred interval is an interval you can choose as a favored change in pitch. It is selected by the number at the right hand side of the slider. The red slider itself sets how likely the preferred interval is to be chosen.
   
• E. Set up the Rhythmic Pattern as shown in the illustration. 
  If you're going to generate several tracks and you want successive tracks to become more busy (see "F" below) then it's a good idea to choose a rather large Start Duration and create a somewhat sparse Rhythmic Pattern as indicated.
   
• F. Check all three checkboxes at the bottom of the window.
  The "Transpose Octave between Track" checkbox will cause each successive track to be an octave higher than the previous one. This helps prevent huge, muddy clusters of notes.
  The "Never repeat notes" checkbox prevents consecutive notes of the same pitch in each track.
  The "Divide Durations between Track" checkbox causes the Rhythm Pattern to be doubled on each successive track. If you start with a fast and busy rhythm pattern (low Start Duration and no rests) you will get very dense sequences from the MultiTrack Random Generator.