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Above: Trained listener Alex Miller is evaluating the sound quality of three loudspeakers in Harman's Multichannel Listening Lab. The automated speaker shuffler ensures that each speaker is heard in the exact same position. The acoustically transparent, visually opaque scrim means the tests are double-blind and not influenced by brand, price or other sighted biases. The computer randomly selects the presentation order of the speakers in each trial and listener controls the switching so that experimenter bias is removed from the test.