Building from a whispering pianissimo to a thunderous fortissimo, a skilled orchestra can leave its audience with goose bumps. Because a wide selection of volumes allows for more expressive performances, a team of researchers investigated if the geometry of the performance venue plays a part in the range of volumes heard by the audience, called the perceived dynamic range. The team attached sensitive microphones to the ears of mannequins and positioned them throughout 10 European concert halls with layouts varying from simple boxes to complex curves. The researchers then performed synthetic symphonies using speakers instead of musicians. The team noted that some sound from the stage bounces off the walls and into the sides of the listeners. Human hearing emphasizes high-frequency sounds when they arrive from the side, enhancing the louder end of the perceived dynamic range. Rectangular "shoebox" concert halls reflected more sound into the sides of the audience , boosting the perceived dynamic range by 2 decibels compared with other layouts, the researchers report online this week in the Proceedings of the National Academy of Sciences. Because a change of 1 decibel is considered noticeable, the researchers say the effect is worth noting when composing plans for new music halls.
ScienceShot: Straight Walls Make Better Concert Halls