Use of a 3-Facet Rasch Model to Measure Small Audio Impairments in the Field of Audio Engineering

10 POPULAR MEASUREMENT Abstract The subjective measurement of small audible differences in the audio engineering field has been hampered by experimental conflicts between applicability and reproducibility. The Rasch Model offers a powerful means of controlling the statistical analysis of experimental data in order to maximize reproducibility and applicability across listeners, audio material, and devices under test. The authors describe their testing of five perceptual audio coders for Lucent Technologies . The Problem of Measuring Perception of Small Audible Impairments Measurement of listener perception of small audible impairments caused by audio reproduction devices has been constrained by the combined but conflicting needs for (a) re producible test results and (b) broadly applicable conclusions . Measurement techniques have sought to achieve reproducibility through rigorous test design and execution intended to minimize such sources of uncontrolled variance as listener training and expertise, the choice of program material, and the listening environment. For example, only expert listeners are used and the listening environment must meet exacting specifications . This poses a dilemma . The more rigorously controlled the testing environment, the less faithfully it reflects the listening conditions of the real world . Most listeners are not experts . Most rooms do not meet the specifications for properly controlled listening environments .