Part of my job at Harman International involves participating in audio dealer training and press events. This involves a 1-2 day field trip to Harman's R&D labs in Northridge where the visitors experience first-hand the listener training process, and participate in a double-blind loudspeaker listening test. Visitors usually leave our labs with a heightened appreciation and respect for the scientific efforts behind the development and testing of new models of Revel, JBL, and Infinity loudspeakers.
A few years ago, Infinity commissioned a video known as "Infinity Academy", aimed at encapsulating the 1-2 day training event onto a DVD. Chapter 6, the "Final Test," discusses listener training and the double-blind listening test, where trained listeners evaluate the Harman prototype loudspeaker against its best competitors. The goal is to achieve "best-in-class" performance, attainable only until the prototype receives a preference rating higher than its best competitor. In the event that the loudspeaker fails on its first attempt, the listeners' feedback is used to re-engineer the loudspeaker, after which, it is re-submitted for another listening test.
The picture to the right shows three loudspeakers on the automated speaker shuffler in the Multichannel Listening Lab. The shuffler brings each loudspeaker into the exact same position within 3 seconds, so that any loudspeaker positional biases are removed from the listening test.