Monday, May 22, 13:00 — 15:30
Sean Olive (Chair)
P18-01 Sensory Profiling of High-End Loudspeakers Using Rapid Methods—Part 2: Projective Mapping with Expert and Naïve Assessors
Davide Giacalone (Presenting Author), Søren Bech (Author), Torstein Boðason (Author), Jakob Lund Laugesen (Author), Samuel Moulin (Author), Maciej Nitkiewicz (Author)
This is the second of a series of papers evaluating the efficiency of rapid sensory profiling methodologies in the audio field . The present paper introduces projective mapping  as a method for perceptual audio evaluation and demonstrates its application for discrimination and description of a set of high-end loudspeakers. Additionally, the suitability of the method with both experts and naïve assessors was evaluated. The results showed a successful discrimination between the loudspeakers with the main differences primarily associated to bass strength and bass depth. A high degree of agreement was observed between perceptual configurations obtained separately by the expert and the naïve assessors, though the former outperformed the latter in the descriptive part of the method.
Convention Paper 9775
P18-02 Potential Audibility and Effects of Ultrasonic Surveillance Monitoring of PA and Life Safety Sound Systems
Peter Mapp (Presenting Author)
Ultrasonic surveillance monitoring, to check the operational integrity of PA and Emergency Communication Systems, has been in existence for over 40 years – particularly in Europe. Since its inception, there has been debate as to the potential audibility that these systems may have. As the vast majority of PA systems engineers and designers have not heard or experienced any effects, is has generally been assumed that the general public do not either. Recently however, concern has been raised and claims of ill effects have been reported. There is however, little or no data as to the ultrasonic sound levels that PA systems actually emit. The paper discusses the results of an initial survey of ultrasound radiated by a sample of some 50 PA systems and compares the results with a number of international standards – there currently being little or no specific guidance. The paper reviews the technology involved, typical emission levels and concludes by making a number of recommendations to assist with the control of ultrasonic emissions from PA systems that should help to mitigate unintended side effects.
Convention Paper 9776
P18-03 Pink Noise Formant Bandwidth Discrimination
Tomira Rogala (Presenting Author)
This paper presents the results of the third part of an experiment aimed to determine discrimination thresholds for timbre of pink noise modified by a formant. The investigated parameter was the Q factor (Q=f/Δf). The Q=3 was used as a reference and the comparison stimuli had Q>3. A 3AFC test paradigm was used. The listeners, who were tonmeisters and non-musicians, were asked to indicate which noise burst in each group of three was a different one. The results indicate that: (1) the Q discrimination threshold as a function of formant frequency has a U shape, (2) tonmeisters better discriminate Q changes than non-musicians, and (3) all listeners improved their scores with practice. Above results are consistent with those reported previously.
Convention Paper 9777
P18-04 The Influence of Program Material on Sound Quality Ratings of In-Ear Headphones
Sean Olive (Presenting Author), Omid Khonsaripour (Author), Todd Welti (Author)
A listening test was conducted to identify music programs that provide sensitive, discriminating, and reliable ratings for in-ear (IE) headphone evaluations. Ten trained listeners gave sound quality ratings for eight models of IE headphones using ten different music programs. A virtualized headphone method was used to provide double blind, controlled presentations in which headphone leakage effects were monitored and eliminated. The main effect on the sound quality ratings was due to headphones while the program produced no significant effects or interactions. However, certain programs produced more discriminating and reliable ratings than other programs, the key factor being the bandwidth of the program’s spectral content, and the subject’s familiarity with it. As expected, the amount of bass content in each program tended to influence the ratings of headphones that had too much or too little bass output in their measured frequency response.
Convention Paper 9778
P18-05 Audio Quality Evaluation in MUSHRA Tests–Influencesbetween Loop Setting and a Listeners’ Ratings
Nadja Schinkel-Bielefeld (Presenting Author)
In many listening tests for audio quality evaluation the listeners have the possibility to set loops, meaning they can focus on a smaller part of the audio signal and listen to that repeatedly. In previous papers we already showed that experienced listeners set more loops and that learning to set loops increases the ability of the listener to perceive artifacts. Now we analyze to what extent these loops chosen by the listener vary from listener to listener and whether the ratings are influenced by the choice of loops of the listener. We show that—depending on the stimulus—listeners who set different loops may also rate significantly different.
Convention Paper 9779