Loudness Patterns—a New Approach

In the past loudness patterns have been based on the masking effect of one sound on another. For complex sounds having distributed energy spectrums this method appears to be valid. For sounds with single frequency components the method is thought to be in error due to the formation of beats and modulation products between the primary tone for which a pattern is desired and the probe tone which is used to determine the pattern details. To avoid these difficulties in the present tests, the probe tone was presented after the primary tone was turned off. The resulting residual masking patterns differ in a number of important respects from patterns based on the simultaneous masking procedure. A comparison between the loudness of a primary tone, as evidenced by the magnitude of its residual masking pattern, with the results of loudness judgment tests was made. This was done by replacing the physical scales of pressure level and frequency by the subjective scales of loudness and position. A reasonably good check of computed and measured loudness values was obtained. Patterns for a 1000-cycle tone were measured to show how the loudness of the standard reference tone is distributed and how this distribution changes as the level of the tone is increased.