- APPLIED ACOUSTICS Journal
- November 2021
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Listening tests are key to evaluate the perception of difference between confusable auditory stimuli, among other purposes. In room acoustics, the usefulness of listening tests is beyond question. They have been extensively employed and have allowed relevant and interesting conclusions to be drawn for different purposes, such as the determination of the just noticeable differences (JNDs) of room acoustical parameters and the evaluation of subtle differences between auralizations, among many others.
However, the lack of methodological consensus has led research with similar goals to yield uneven results. Among the possible causes is the fact that different testing protocols are employed to present the stimuli and to question the participants, which can have a significant influence on the discrimination abilities if the sensitivity of the various protocols is not comparable. In room acoustics, nevertheless, few studies have been conducted so far to assess the impact that these protocols may have on discrimination. Consequently, it might be of great interest to carry out experiments aiming to compare several protocols with a population of participants as wide as possible.
In this context, the purpose of this research is to evaluate the operational power of several protocols that can be employed to compare confusable auditory stimuli. To this end, a listening test has been carried out on a large population of 134 participants in which the discrimination performance of seven protocols has been assessed. Some of these protocols have been selected among the most widely used in room acoustics, while others have been chosen as they have been found to be operationally powerful in other fields of sensory discrimination.
The results, analyzed by means of the Thurstonian measure of sensory difference d-prime (d¿), have allowed to assess the operational power of each protocol, as well as to evaluate the influence that experimental effects such as those of sequence, learning and fatigue have on their discrimination capabilities. This evaluation has revealed that the protocol has a significant influence on the discrimination ability, making it important to pay close attention to this fact when designing listening tests in room acoustics. Furthermore, it has allowed to identify the most recommended protocol among those tested in the study regarding both its remarkable operational power and its low propensity to experimental effects.
- room acoustics; listening test; operational power; difference testing; cognitive decision strategies