The Headphone and Loudspeaker Test-Part II: A comprehensive method for playback device screening in Internet experiments.

HALT (The Headphone and Loudspeaker Test) Part II is a continuation of HALT Part I. The main goals of this study (HALT Part II) were (a) to develop screening tests and strategies to discriminate headphones from loudspeakers, (b) to come up with a methodological approach to combine more than two screening tests, and (c) to estimate data quality and required sample sizes for the application of screening tests. Screening Tests A and B were developed based on psychoacoustic effects. In a first laboratory study (N = 40), the two tests were evaluated with four different playback devices (circumaural and intra-aural headphones; external and laptop loudspeakers). In a final step, the two screening tests A and B and a previously established test C were validated in an Internet-based study (N = 211). Test B showed the best single-test performance (sensitivity = 80.0%, specificity = 83.2%, AUC = .844). Following an epidemiological approach, the headphone prevalence (17.67%) was determined to calculate positive and negative predictive values. For a user-oriented, parameter-based selection of suitable screening tests and the simple application of screening strategies, an online tool was programmed. HALT Part II is assumed to be a reliable procedure for planning and executing screenings to detect headphone and loudspeaker playback. Our methodological approach can be used as a generic technique for optimizing the application of any screening tests in psychological research. HALT Part I and II complement each other to form a comprehensive overall concept to control for playback conditions in Internet experiments.

The Headphone and Loudspeaker Test - Part I: Suggestions for controlling characteristics of playback devices in internet experiments.

In internet experiments on auditory perception, playback devices may be a confounding variable reducing internal validity. A procedure to remotely test multiple characteristics of playback devices does not currently exist. Thus, the main goals of this study were to (i) develop and (ii) evaluate a comprehensive, efficient, and easy-to-handle test procedure for the reliable control and identification of playback device characteristics in online experiments. Based on a counting task paradigm, the first part of the Headphone and Loudspeaker Test (HALT-Part I) was developed with which researchers can standardize sound level adjustments, detect stereo/mono playback, and assess lower frequency limits. In a laboratory study (N = 40), HALT-Part I was evaluated with four playback devices (circumaural and intra-aural headphones; external and laptop loudspeakers). Beforehand, the acoustical properties of all playback devices had been measured (e.g., sound pressure level, frequency response, total harmonic distortion). The analysis suggested that HALT-Part I has high test-retest reliability (rtt = .90 for level adjustment and rtt = .79 for stereo/mono detection) and is an efficient (3.5 minutes for completion) method to remotely test playback devices and listening conditions (sound level, stereo/mono playback). The procedure can help improve data quality in internet experiments.

Wrapped into sound: Development of the Immersive Music Experience Inventory (IMEI).

Although virtual reality, video entertainment, and computer games are dependent on the three-dimensional reproduction of sound (including front, rear, and height channels), it remains unclear whether 3D-audio formats actually intensify the emotional listening experience. There is currently no valid inventory for the objective measurement of immersive listening experiences resulting from audio playback formats with increasing degrees of immersion (from mono to stereo, 5.1, and 3D). The development of the Immersive Music Experience Inventory (IMEI) could close this gap. An initial item list (N = 25) was derived from studies in virtual reality and spatial audio, supplemented by researcher-developed items and items extracted from historical descriptions. Psychometric evaluation was conducted by an online study (N = 222 valid cases). The N = 222 Participants (female = 112, mean age = 38.6) were recruited via mailing lists (n = 34) and via a panel provider (n = 188). Based on controlled headphone playback, participants listened to four songs/pieces, each in the three formats of mono, stereo, and binaural 3D audio. The latent construct "immersive listening experience" was determined by probabilistic test theory (item response theory, IRT) and by means of the many-facet Rasch measurement (MFRM). As a result, the specified MFRM model showed good model fit (62.69% of explained variance). The final one-dimensional inventory consists of 10 items and will be made available in English and German.