The basic idea is to load two sound files into the patch and play them at very low varying speeds. The default setting is a speed between 10 and 20 percent, a new value is chosen by a chance operator every 10 seconds, and slowly accelerating or slowing from one value to the other. Both channels work independently. Aditionally L-R-panning supports the sound-colour shifts.
The frequency for the chance operator as well as a minimum value and a range can be adjusted.
From my experience especially disharmonic, bell-like sounds, pads, or rhythmic musical materials fit very well, while vocals or stressed drum sounds might lead to unsatisfying results. But as this is only what I witnessed from my limited experiments, I am glad for other opinions. Don’t forget to switch to presentation mode after opening the patch.
I would really appreciate any feedback or audio files of your own results with the patch for further improvement, just write a comment.
Two examples realized with the "Drone Creator"
-----The following is the original description from my project "Aurora Drone"-----
“Aurora Drone” is the attempt to completely alter the character of a piece of music by playing it back at very low speeds. It is thus possible to change a very vivid Drum and Bass track into a minimalistic soundscape. With a Max/MSP patch that I programmed and called “Drone Creator” you can play up to two sound files at a time and the implemented chance operators immediately start to slowly modulate the play back speed (and therefore pitch) for both tracks independently, creating continuously changing layers of sound and rhythm. In this case I chose a Drum and Bass song called “Aurora” (https://www.youtube.com/watch?v=gqm1g8AFc8U
) that I produced previously and which is played twice simultaneously at speeds between a factor of 0.1 and 0.3 of the original speed. Additionally both tracks are moving between the left and right channel contributing the shifting sounds in this piece. With the Drone Ceator it is possible to produce an immeasurable amount of sounds not limited to drones by the choice of the musical material fed into it as well as the variation of the parameters.