Another ‘‘new’’ metric for outdoor amphitheater criteria

Abstract

Since the late 1960s, when amplified musical performances began being held there, Atlanta’s open-air Chastain Park Amphitheater has been the source of enormous friction between the City, the venue’s owner, and the wealthy, politically-connected residential community abutting the Park. To identify the characteristics of concert event sound to which neighbors are particularly sensitive, sound levels were monitored during 17 concerts, ranging from quiet jazz and classical performances to rock-and-roll and hip-hop. Community sound levels were monitored at 25 locations, including nine where measurements were made simultaneously inside and outside homes. The study team confirmed that low-frequency sound was the one feature of concert-related sound that community residents identified as most problematic, but that only a relatively small proportion of the Chastain concerts resulted in any significant community annoyance. After assessing the spectral characteristics of the most troublesome concerts, a new compliance metric has been proposed to address low-frequency annoyance issues: a two-tiered exceedence threshold, based on 1-minute LEQ levels in the 63 Hz octave band measured at the rear of the amphitheater, with a concert-event ‘‘exceedence’’ defined to be either a 1-minute LEQ(63 Hz) level greater than 95 dB or more than ten 1-minute LEQ(63 Hz) levels greater than 90 dB.