Create Digital Music has a post about a free reverb plugin with someinterestingcharacteristics
Urs Heckmann just combined ‘reverb’ with ‘experimental, possibly sonically unstable plug-in with unpredictable results.’ And it’s free.
Protoverb is an “experimental” reverb from u-he built around the idea of modeling series of resonances and reflections in a room. In my play so far, I’ve found distinct memories echo clearly (“ghost echoes,” as the developers put it), while richer ambiences create strange, beautiful ringing sounds.
The reason reverbs generally aren’t built this way is that the results can be unexpected or even unpleasant – but that’s what makes this such fun. Even a single parameter can produce a broad range as you adjust wet/dry feedback. And by adjusting other settings, you can produce sounds ranging from artificial to realistic to … awful.