Imager allows you to expand or reduce the stereo width of your audio in up to 4 bands. This way, you can independently adjust the stereo image in defined frequency domains.
MonoToStereo turns a mono signal into a pseudo-stereo signal. The plug-in can be used on a mono file or a stereo file with equal channels.
StereoEnhancer expands the stereo width of (stereo) audio material. It cannot be used with mono files.