For precise wave-based room acoustics modeling, an accurate extended-reaction (ER) sound absorber model must be formulated to assess frequency and incident-angle dependences of a sound absorber. Two novel efficient time-marching schemes with implicit time-domain FEM (TD-FEM) are presented to model the extended reacting boundary of microperforated panel (MPP) sound absorbers. Generally, MPP absorbers (MPPAs) have an air cavity behind them, which causes ER behavior. Formulating the ER behavior of MPPAs is necessary for simulating room acoustics. A hindrance to the time-domain modeling of the ER of MPPAs is the need to treat its complex impedance on the microperforations. The proposed schemes model MPPs as interior boundary conditions and deal with the complex transfer impedance with auxiliary differential equations (ADEs), producing stable schemes after the Crank–Nicolson solver is applied. For scheme verification, the impedance tube model with a single-leaf MPPA is analyzed. Additionally, the effectiveness of the proposed schemes is assessed by practical room acoustics modeling involving MPPAs and comparison with a frequency-domain FEM solver, which can address complex transfer impedance exactly. The results show excellent performance of the proposed methods. The TD-FEMs can model room acoustics, including the MPPA, O(100) times faster while maintaining accuracy comparable to that of FD-FEM.

This study was conducted to elucidate the actual situation of noise levels around roundabouts in Japan and to develop an energy-based prediction method to calculate equivalent noise levels around roundabouts. Two roundabouts in Fukuoka Prefecture in Japan were surveyed to clarify the noise levels around them. The correspondence between calculated and measured noise levels would be better if the sound power levels of Common Noise Assessment Methods in Europe (CNOSSOS-EU) were applied with further reduction of about 3 dB. In small roundabouts typically introduced in Japan, vehicles pass slowly at an almost constant speed. Therefore, setting the sound power level while assuming the steady running of vehicles at low speeds is appropriate. Measurement survey results clarified that a vehicle speed about 20 km/h on circulatory roadways is appropriate and also clarified that the formula for steady running can be used by applying the sound power level used for ASJ RTN-Model 2018. We propose a method of predicting equivalent noise levels by calculating single-event noise exposure levels from unit patterns according to the ASJ RTN-Model 2018 prediction procedure. The calculation and measurement results at 25 points around two roundabouts show good agreement. The findings confirmed that this proposed calculation method can accurately predict equivalent noise levels around roundabouts.

We conducted a psychophysical experiment to investigate how a combination of direct and reflected sounds affects perception of sound image. When a direct sound (leading sound) is followed by a reflection (lagging sound), it induces the precedence effect (PE), the summing localization (SL), and the split of sound image (SSI). Previous studies have explored these effects with lagging sounds from the horizontal and median planes, but the influence of oblique reflections, which appear in real environments, on the perceived sound images remains unknown. Our experiment evaluates the conditions under which PE, SL and SSI occur when a leading sound originates from the front and a lagging sound arrives from an oblique direction (θ,φ). Comparing the perceived sound image when an oblique lagging sound was presented to those with horizontal (θ,0) and vertical (0,φ), it is suggested that the sound image localization with an oblique lagging sound is a combination of azimuthal localization for a horizontal lagging sound and elevation localization for a vertical lagging sound.

A method for analyzing the sound pressure and sound-particle velocity in sound fields using cardioid microphones—that is, the c-c method—was developed. First, the response and directivity of a cardioid microphone were defined using the sound pressure and particle velocity in the sound field. Unlike conventional definitions, these new definitions were generalized mathematical models that did not assume a specific sound source or sound field, the c-c method algorithm being derived from these definitions. To verify the new response and directivity definitions, as well as the c-c method itself, experiments were conducted in near-sound fields where the sound pressure and particle velocity did not exhibit the same phase. Consequently, the directivity changed with distance from the sound source and frequency. This change corresponded well with the theoretical value generated using the proposed model, demonstrating the validity of the new directivity definition, even in the near-sound field. The sound-pressure and particle-velocity measurement results obtained using the c-c method corresponded well with the theoretical values. These results demonstrated the c-c method to be valid, even in the near-sound field.

Acoustic intensity estimation is an important research topic in the field of architectural acoustics. Various point-based intensity estimation methods using microphone probes have been proposed so far. On the other hand, research has also been conducted on average acoustic intensity field estimation methods using microphone arrays. This study proposes a method for estimating instantaneous sound intensity fields that can be applied to arbitrary spatial dimensions and array configurations. The proposed method is based on representing the instantaneous sound field using the reproducing kernel of a space of spherically band-limited functions. One of the key advantages of the proposed is its ability to analytically handle the spatial differentiation involved in the calculation of particle velocities, allowing for more accurate intensity estimation compared to the p-p method. Numerical simulations were conducted to validate the effectiveness of the proposed method, using a three-dimensional plane wave sound field.

Understanding of gameplay can enhance the experience and entertainment of video game. In this study, we propose to utilize the sound generated by a controller for analyzing the information of gameplay. Controller sound is a user-friendly feature related to gameplay because it can be very easily recorded. As a first step of the research, we performed identification of characters of Super Smash Bros. Ultimate only from controller sound as an example task for examining whether controller sound contains valuable information. The results showed that our model achieved 79% accuracy for identification of five characters only using the controller sound.