It works by adding a phase-inverted, discrete chorus with a slight delay to the dry signal. Unlike a typical chorus effect (which is supposed to turn a solo-instrument into an ensemble sound) this stereoizer is more transparant. Its also not a typical "delay" effect, or a "surrounder" which isn't really mono-compatible.
This plug-in is mono-compatible: People who listen to your music in mono will not hear the stereoizer at all ! They will only hear the dry signal. This has the benefit that you can use it, for example on bass sounds. Stereoized basses won't sound bad on sound-systems where there are only one loudspeaker (sub-woofer) for the bass.
But you should be careful with the MIX fader: When you go beyond 90 degrees (in other words, when you move the fader down on the red area) the sound will begin to decrease in volume for people who listen to your music in mono. This is because the dry signal will begin to derease in volume when you go below mid position. The signal that remains, is the phase-inverted signal (the wet signal).
Mp3 demos - each mp3 preview contains unprocessed sound first and then processed by Stereoizer:
Download: Stereoizer v1.1