An Assesment of dB(A) for Predicting Loudness and Annoyance of Noise Containing Low Frequency Components

Abstract

The value of dB(A) as a predictor of loudness and annoyance for noise with low frequency components has been assessed in an experiment using a matching technique. Twenty subjects compared two noise stimuli within the dynamic range 49–86 dB(A) by adjusting one of the sounds until it appeared as equally loud or equally annoying as the other. One noise was dominated by energy in the low frequency range 15–50 Hz. In the other sound this 15–50 Hz component was weak. At equal dB(A) levels, the noise dominated by the low frequency component was perceived as 4–7 dB louder and 5–8 dB more annoying than the other noise. Other frequency weightings were assessed; PLdB underestimated loudness to the same extent as the dB(A), while dB(C) overestimated. The dB(B) and dB(D) were more closely in accordance with experimental results, but they nonetheless underestimated by up to 3–4 dB. Methodological problems in connection with the matching technique are discussed.