Sound pressure level (SPL) is the standard metric for regulations regarding environmental noise exposure. Because performances are often regulated by their A‑weighted sound level, it is tempting to think that A‑weighted level should be the primary design consideration for sound system headroom. Because A‑weighting disregards significant low‑frequency energy, it is possible to create a wide variety of spectra, all of which have the same A‑weighted level, but each of which has a different C‑weighted level and spectral shape. While excessive A‑weighted levels are considered by regulations to be correlated with hearing damage, A‑weighted levels are less well correlated with community annoyance. In recognition of this The Netherlands has created a permitting system that incorporates the difference between C‑ and A‑weighted sound levels (C‑A) as measure for low‑frequency content. This paper gives supporting evidence for different C‑A levels being correlated with different genres of music, and offers complementary design guidance corresponding to sound system headroom with emphasis on in‑band levels.
https://www.aes.org/e‐lib/browse.cfm?elib=21731
