Michael Schoeffler

Human ability of counting the number of instruments in polyphonic music

There are indications that humans are only able to correctly count up to three voices in polyphonic music pieces of homogeneous timbre, where each voice is played by the same instrument. A more general case, where voices are played by instruments of inhomogeneous timbre, has not been fully addressed so far. In order to approach this question we conducted a listening experiment with 62 participants to find out whether both scenarios - instrumentation by inhomogeneous or homogeneous timbre - share the same outcome. This paper describes the design of the experiment including an analysis of the results, which show that both scenarios are related. Furthermore, a detailed analysis of the error rates in correctly counting the number of instruments reveals that there are significant differences between non-musician and musician listeners, in particular regarding the upper auditory limit of the number of correctly counted instruments. Based on these results, models for the perception of instruments in auditory str...

On the validity of virtual reality-based auditory experiments: a case study about ratings of the overall listening experience

In recent years, new developments have led to an increasing number of virtual reality (VR)-based experiments, but little is known about their validity compared to real-world experiments. To this end, an experiment was carried out which compares responses given in a real-world environment to responses given in a VR environment. In the experiment, thirty participants rated the overall listening experience of music excerpts while sitting in a cinema and a listening booth being in a real-world environment and in a VR environment. In addition, the VR system that was used to carry out the sessions in the VR environment is presented in detail. Results indicate that there are only minor statistically significant differences between the two environments when the overall listening experience is rated. Furthermore, in the real-world environment, the ratings given in the listening booth were slightly higher than in the cinema.

Towards a listener model for predicting the overall listening experience

Listeners have different preferences when it comes to rating the overall listening experience while listening to music. Therefore, a listener model for predicting the overall listening experience must consider sensory, perceptual, cognitive and psychological aspects rather than solely rely on perception-based attributes (e. g. audio quality) of the music signal. In this work, a generic model framework is defined for modeling a listener while taking part in an auditory experiment. In addition, a subset of the model is used to describe algorithms for predicting the overall listening experience based on experimental results. Thereby, the results of two experiments are utilized to define a prediction algorithm for the cases of bandwidth-degradation stimuli and playback by different reproduction systems.

Evaluation of Spatial/3D Audio: Basic Audio Quality Versus Quality of Experience

During the past decades, spatial reproduction of audio signals has evolved from simple two-channel stereo to surround sound (e.g., 5.1 or 7.1) and, more recently, to three-dimensional (3D) sound including height speakers, such as 9.1 or 22.2. With increasing number of speakers, increasing spatial fidelity and listener envelopment are expected. This paper reviews popular methods for subjective assessment of audio. Moreover, it provides an experimental evaluation of the subjective quality provided by these formats, contrasting the well-known basic audio quality (BAQ) type of evaluation with the more recent evaluation of overall listening experience (OLE). Commonalities and differences in findings between both assessment approaches are discussed. The results of the evaluation indicate that 3D audio enhances BAQ as well as OLE over both stereo and surround sound. Furthermore, the BAQ- and OLE-based assessments turned out to deliver consistent and reliable results.

The Influence of Audio Quality on the Popularity of Music Videos: A YouTube Case Study

Video-sharing websites like YouTube contain many music videos. On such websites, the audio quality of these music videos can differ from poor to very good since the content is uploaded by users. The results of a previous study indicated that music videos are very popular in general among the users. This paper addresses the question whether the audio quality of music videos has an influence on user ratings. A generic system for measuring the audio quality on video-sharing websites is described. The system has been implemented and was deployed for evaluating the relationship between audio quality and video ratings on YouTube. The analysis of the results indicate that, contrary to popular expectation, the audio quality of music videos has surprisingly little influence on its appreciation by the YouTube user.