Abstract
The Concept of Equal Sound Pressure Curve is proposed by Flecher and Munson at Bell Labs to reveal the auditory sense of human in 1930's. Later, The gap between actual and early ELC: equal Loudness Contour is pointed our especially in low frequency band less than 1kHz. AIST-JAPAN established new ELC to compensate low frequency sensitivity. The A - Chracteristics in ELC is adopted to Noise Meter. However, it is recognized there exist gap between noise level and loudness level. To investigate the gap between loudness and noise(discomfort) level, we measured the frequency related discomfort index with organoleptic assessment. Experiment result shows the discomfort index is sound pressure dependent and sensitive to aging factor.
