Untrained listeners reach quick, consistent sound-quality judgments when switching is instantaneous and sequence-blind.

Evidence

Listeners were professional colleagues, friends interested in audio, and a few audio journalists. Some were amateur musicians. None was a “trained” listener, but all who participated on a regular basis became very adept at the task. Switching among the loudspeakers was instantaneous. Many tests involved single listeners—the best method. Others involved two or three at a time who shared control. This was not ideal, because the switching sequence quickly revealed which loudspeakers the person in control was favoring and which were being ignored. An independent operator following a randomized sequence, and switching at suitable intervals was preferred. Several musical selections were used—classical, jazz and popular. There was no time limit, but it became clear that, with experience, decisions were made quickly. — Toole, Floyd E, Sound reproduction- the acoustics and…, 175

Categorization

• SEED: An essay angle: the experimental-design lesson that single blind listeners with randomized switching outperform shared-control tests — a general principle for any perceptual/sensory evaluation methodology.