I saw this posted on the REAPER forum today. I always wondered what a phase rotator does and this gif pretty much explains it, I don’t really care how but I know it makes a big difference. When the polarity button and delays don’t do the trick, a phase rotator like Phasebug comes in handy. What an awesome tool!
Get Phasebug VST for free here: http://www.betabugsaudio.com/plugs.php
Hardware units that do this trick while recording are also available:
Little Labs IPB http://littlelabs.com/ibp.html
Radial Phazer http://www.radialeng.com/re-phazer.htm