Few things have changed my views on audio as sitting in this room and voting for speakers "blind." Here is what the setup looks like and nice history of it from Dr. Sean Olive. Only 11 minutes and "must watch:"
One of the excuses for not doing double blind test of speakers is the high cost of the speaker shuffler room Harman uses above. But this need not be the case. Their multi-channel room has a simple rotating triangle that can swap out speakers and audio devices quickly to same end: