I've found a good trick this morning !!!
Instead of thinking about axis (X and Y) where each of the four audio sources is along these axis (axis X : source A & source C - axis Y : source B & source D), the idea was to think about a square where each corner is an audio source. Here is what I've done ...
1 - I cut my 4 loops to the same length (16 bars in this case) and put each on its own track.
2 - Right-click on each audio clip and convert them with "Slice in a new MIDI track".
3 - Select the smaller resolution you can have (here 1/8 bar give 128 slices) and for Slice Preset select "Slice to simgle Sampler".
4 - Now you should have 4 new MIDI tracks in which you have a single Sampler instrument playing a 16 bar MIDI loop triggering 128 sample slices of the former audio loops =>
Loop 1, Loop 2, Loop 3, Loop 4.
5 - Create a new MIDI track, copy the first Sampler instrument in it (
Loop 1), and copy the MIDI clip too.
6 - Create a rack with this Sampler instrument and copy in it the second Sampler instrument (from the 2d audio loop :
Loop 1) =>
Rack 1-2 with MIDI triggered loops 1 & 2.
7 - Embedded
Rack 1-2 into an new rack =>
Main Rack.
8 - Duplicate
Rack 1-2 and rename the copy
Rack 3-4.
9 - Copy into
Rack 3-4 Sampler instruments
Loop 3 and
Loop 4, and delete Sampler instruments
Loop 1 and
Loop 2 which were copied when we have duplicated
Rack 1-2 (see previous
step 8).
10 - Now in each sub-racks (
Rack 1-2 and
Rack 3-4), click on the
CHAIN button and draw a crossfade with respectively
Loop 1 and
Loop 2, and
Loop 3 and
Loop 4.
11 - For each sub-racks (
Rack 1-2 and
Rack 3-4), assign a circular knob to control the crossfade between respectively
Loop 1 and
Loop 2, and
Loop 3 and
Loop 4.
12 - On the
Main Rack assign a circular knob to control both knob from
Rack 1-2 and
Rack 3-4, and label it
Fade X.
13 - On the
Main Rack, click on the
CHAIN button and draw a crossfade between
Rack 1-2 and
Rack 3-4 and assign a second circular knob to control the main crossfade. Label it
Fade Y.
14 - Assign MIDI controller to knobs b]Fade X[/b] and b]Fade Y[/b] and have fun !!!
NOTES
- You should make some minors level adjustments in each of the 4 Sampler instruments to get a good audio balance.
- If you are using a MIDI joystick (I'm using the one in my Faderfox micromodul LV2), each corner is an audio source. Making circles with the joystick crossfade between the 4 audio sources.
- If you put the joystick in the central position, you may get a kind of "bad spot" audio level, but it depends on your audio materials too.
