http://www.gfisystem.com/specular-tempus.html This algorithm allows you to capture a brief snapshot of the sound you are playing, and hold it indefinitely, then you can play over it (with reverberation).
1-Layer mode : You can fade out the sustained sound, and immediately fade in a new one.
N-Layers mode : You can add infinite number of layers of sustained sound, creating an ever-dense ambience goodness!
1. Adjust Blend and Decay knob to get the desired amount of reverb mix and reverb time. Leave Param and Intensity knobs at midpoint.
2. Press and hold down both footswitches, when the LEDs start flashing the pedal began to continuously capture a snapshot of whatever you are playing. When you release the footswitch, the pedal will take the last 0.25 seconds of the captured sound and hold it indefinitely.
3. Now adjust Intensity and Param to get the desired level and tonality for the sustained sound. The Intensity knob runs backward : sound gets louder as knob is turned counter-clockwise.
Now you can play over the sustained sound, and when you want to change the sustained sound with a new one, simply repeat step-2; the current sustained sound will fade out and then you can fade in a new one. The new sound will fade in to the level you’ve set previously. Or alternatively, use the N-Layers mode to add more-and more layers on top of existing ones.