Effect of loudspeaker position and model on cognitive load, quality, clarity, and sentence recognition performance

We sought to determine the effects of classroom loudspeaker position, model of loudspeaker, and talker accent on mental effort or cognitive load, word clarity, sound quality, and word recognition. Thirty-one typically-developed university students whose native language is English rated and transcribed recorded sentences produced by a native English talker and a native Dutch talker speaking English. The listeners were seated in acoustically pre-calibrated locations in a classroom and were presented 10 sentences at conversational level in each of four randomized conditions: from a conventional classroom loudspeaker in front or mounted above them, and from a loudspeaker optimized for speech reproduction placed in front or mounted above them. At the front of the classroom was a muted video recording of one of the talkers delivering an online lecture. Results showed front-located speakers yielded less cognitive effort, better sound quality, and better word clarity-showing importance of congruence of loudspeaker/talker position.