Loudness Asymmetries for Tones with Increasing and Decreasing Levels

Studies of loudness change for tones with linearly varying levels using different loudness rating methods, such as direct estimation or indirect estimation based on the start and end levels, have revealed an asymmetry depending on the direction of change (increasing vs decreasing). The present study examines loudness asymmetry between increasing and decreasing levels for 1-kHz tones over the range 60-80 dB SPL and over four ramp durations (2, 5, 10 and 20 s) using direct global and continuous loudness ratings made by subjects. Three measures extracted from continuous ratings (loudness duration, loudness change, loudness slope), on the one hand, and the global loudness rating, on the other hand are examined and analyzed separately. Measures extracted from continuous ratings do not reveal any significant perceptual asymmetry between an increasing and a decreasing ramp. However, direct estimation of the global loudness is higher for an increasing ramp than for a decreasing ramp. This result can be explained by a short-term auditory memory effect called the "recency effect".