Sungyoung Kim

An assessment of individualized technical ear training for audio production

An individualized technical ear training method is compared to a non-individualized method. The efficacy of the individualized method is assessed using a standardized test conducted before and after the training period. Participants who received individualized training improved better than the control group on the test. Results indicate the importance of individualized training for acquisition of spectrum-identification and spectrum-matching skills. Individualized training, therefore, should be implemented by default into technical ear training programs used in audio production industry and education.

Rendering an immersive sound field using a virtual height loudspeaker: Effect of height-related room impulse responses

In order to provide consumers more enhanced and immersive experience in sound, most of the new multichannel reproduction formats highlight the significance of height-related information. In this paper, we investigated the influence of height-related room impulse responses when reproduced via various “height-loudspeakers,” including a virtual loudspeaker. Test participants listened to the corresponding sound fields and rated their perceived quality in terms of spaciousness and integrity. The results showed that perceived quality was affected by height loudspeaker positions and height signals, which was a specific room impulse response coupled with a virtual loudspeaker rendering process.

Active field control using sound field generation technique—Case study of a Live concert at a virtual Renaissance church

In the Renaissance area, musical culture was centered at and spread across churches. In order to appreciate Renaissance music, therefore, it is important to account for the influence of acoustics of churches at that era so that audiences today can experience homogeneous musical appreciation. We used an Active Field Control system to create the acoustics using measured the impulse responses (IRs) of a church. The system consists of directional microphones, head amps, a convolution engine, a matrix processor, amplifiers, and loudspeakers. And it picks up the direct response of performance, convolves it with the measured IRs, and reproduces the resulting sound using loudspeakers around the room. Loudspeaker positions in the performance hall are equivalent to the positions where the IRs had been measured at the church. This technique allows us to convincingly recreate not only the reverberation time but also the spatial impressions of the church at the performance hall. In addition, we modified the IRs so tha...

Comparison of Japanese and English language descriptions of piano performances captured using popular multichannel microphone arrays

In a cross‐cultural comparison of musical sound evaluations, the way in which bipolar adjective pairs are used by native speakers of Japanese and English language was studied via a subjective rating task. These ratings were collected in response to eight solo piano performances that had been captured using four popular multichannel microphone arrays, reproduced via a standard 5‐channel loudspeaker array, re‐recorded binaurally, and finally presented via headphones. This allowed nearly identical stimuli to be presented to all listeners, without any modulation of the loudspeaker signals via listener head movements. Average ratings were compared to acoustical measures made on the 32 binaural stimuli, and to salient perceptual dimensions that previously had been derived from pairwise dissimilarity ratings between the stimuli. Results showed close agreement in how the selected terms were used by native speakers of Japanese and English language in the context of this study.

Factors differentiating the 22.2- and 2-channel reproduced sound fields through an acoustic modeling of three listening rooms

We have simulated two loudspeaker configurations (22.2- and 2-channel reproduction) using the CATT-Acoustic software and analyzed the influence of room acoustics on the perception of multichannel-reproduced music. With the rapid growth of virtual reality (VR) and mixed reality (AR), there is a need for an immersive acoustic system that can maintain compatibility of auditory impressions in various acoustic conditions. The research question of the authors’ project is whether an increased number of reproduction channels would reduce the room-induced perceptual difference. To answer this question, we have analyzed physical characteristics from calculated impulse responses (IRs) of three distinct room models (varying dimensions and reflecting surfaces). Among many characteristics, the early decay time (EDT) and clarity (C80) values covary with the loudspeaker configurations. The IRs calculated from a 22.2-channel reproduction system had different EDT and C80 values for all three rooms. The change was more evid...

An assessment of a spatial ear training program for perceived auditory source width

The authors propose a training program for a listener to quantify the horizontal extension of an auditory image-auditory source width (ASW). The proposed program controls the ASW of a five-channel sound source by spreading it across five front loudspeakers, displays the corresponding change in visual width, and trains listeners to remember the spread angle through an isomorphic mapping to the corresponding visual cue. To evaluate the efficacy of the training, the authors conducted pre- and post-training tests. The results show that the width judgment error of the post-training test was significantly smaller than the pre-training test.

Exploration of perceptual differences of virtually enhanced sound fields using timbre toolbox

In this presentation, we approach the analysis of perceived spatial differences from the perspective of timbre using the Timbre Toolbox [Peeters et al., 2011, J. Acoust. Soc. Am., 130, 2902–2916]. The Timbre Toolbox, using MATLAB, calculates 88 descriptors that have been reported in various timbre perception literature. These include temporal (such as RMS energy), spectral (both in magnitude and power spectra), and harmonic descriptors, as well as those based on the Equivalent Rectangular Bandwidth (ERB) model, which approximates the auditory processing. Analyses were performed on 27 stimuli of nine string quartet groups performing one excerpt in three room conditions, as well as the data from perceptual experiments reported in an earlier study [Chon et al., 2015, Proc. Audio Eng. Soc.]. The three room conditions have different spatial profiles, which consist of one natural room and two virtually enhanced rooms, where many physical parameters were closely controlled (e.g., ST1 and ST2). The experimental d...

Comparing the binaural recordings of 22.2- and 2-channel music reproduced in three listening rooms

A room interacts with sound sources. It alters both timbral and spatial impression of produced and reproduced sound field(s), and affects the overall sonic experiences. In this study, we approached the room-induced effect in the context of an immersive audio rendering, and investigated a relationship between room acoustics and audio reproduction formats. First, three classical music pieces were recorded and mixed optimally for the 22.2- and 2-channel reproduction formats. Subsequently, we generated a set of binaural responses to each of 22.2- and 2-channel reproduced music at three distinct listening rooms (varying dimensions and reflecting surfaces). Eleven listeners participated in a listening experiment; they compared two randomly selected binaural stimuli and rated perceived dissimilarity. The collected ratings were analyzed through the individual differential scaling (INDSCAL) to determine a perceptual space of the stimuli. The results show that (1) the listeners perceived the stimuli differences thr...

Efficacy of a new spatial ear training program for “Ensemble width” and “Individual source width”

The authors have devised a matching-based training paradigm that assists listeners in evaluating spatial width of a reproduced sound field with increased sensitivity and memory. The program uses a learning paradigm of repeated comparison and match to references. All sound sources were horizontally spread using a pairwise constant power panning law over front five loudspeakers located at + -60, + -30, and 0 degree. Trainees were asked to adjust a parameter controlling the panning intervals of five-channel sound sources until it matched to the perceived width of a given reference. The program provided visual feedback for isomorphic mapping. To make the training equipment more accessible, the headphone version of the program was also developed using a simulation of listener and sound sources positions in a room. Thirty participants were divided into three groups: a group with loudspeaker-based training, a group with headphone-based training, and a group without training. Participants in the trained groups to...

Investigating integration between auditory and visual location information presented in an augmented-reality device

Effective rendering technique of auditory information for an augmented reality (AR) device has been investigated. Researchers and industries are searching for new applications incorporating AR and Virtual Reality (VR) technologies, which provide enhanced user-experience of interactivity and intimacy. To utilize these benefits best, homogeneous integration between visual and auditory information is important. To date, the binaural technology based on head-related transfer function (HRTF) has been used to create immersive and three-dimensional audio objects for VR and AR devices. In this study, we compared the HRTF method with a stereophonic panning method that only controls Inter-aural Level Difference (ILD) for an AR device (a smart see-through glass) and investigated the precision of auditory information required for a coherent representation with a target visual image at the locations of 0 degree, -5 degrees, and -10 degrees in a counter clockwise. Auditory stimuli were rendered to have target locations...