Peter Lundén

Psychoacoustic evaluation as a tool for optimization in the development of an urban soundscape simulator

This paper will discuss the use of psychoacoustic evaluation as a tool for optimization of the soundscape simulator developed in the Listen project. The listen project is a three-year research project focused around developing a demonstrator, which auralizes the sound environment produced by road and railway traffic. The resolution of the parameter space of the simulator heavily influences the performance of the simulator. The perceptual resolution of the parameter space is investigated and the resolution is adjusted accordingly. The most important parameter is velocity. Adjustments of the resolution of this parameter alone gives a 60% reduction of the usage of memory.

Similarity and pleasantness assessments of water-fountain sounds recorded in urban public spaces

Water fountains are potential tools for soundscape improvement, but little is known about their perceptual properties. To explore this, sounds were recorded from 32 fountains installed in urban parks. The sounds were recorded with a sound-field microphone and were reproduced using an ambisonic loudspeaker setup. Fifty-seven listeners assessed the sounds with regard to similarity and pleasantness. Multidimensional scaling of similarity data revealed distinct groups of soft variable and loud steady-state sounds. Acoustically, the soft variable sounds were characterized by low overall levels and high temporal variability, whereas the opposite pattern characterized the loud steady-state sounds. The perceived pleasantness of the sounds was negatively related to their overall level and positively related to their temporal variability, whereas spectral centroid was weakly correlated to pleasantness. However, the results of an additional experiment, using the same sounds set equal in overall level, found a negative relationship between pleasantness and spectral centroid, suggesting that spectral factors may influence pleasantness scores in experiments where overall level does not dominate pleasantness assessments. The equal-level experiment also showed that several loud steady-state sounds remained unpleasant, suggesting an inherently unpleasant sound character. From a soundscape design perspective, it may be advisable to avoid fountains generating such sounds.

Uni-Verse Acoustic Simulation System: interactive real-time room acoustic simulation in dynamic 3D environments

Uni‐Verse Acoustic Simulation System (UVAS) is a newly developed interactive room acoustic simulation system that can handle dynamically changing 3D geometric models in real‐time. The system can share such models with other application, such as visual renderers or 3D modeling tools, over a network using the Verse protocol. UVAS is implemented using the beam‐tracing method. It is build as two separate but highly integrated parts. The first part is handling the geometry, its responsibility is to find audible sound sources and relevant reflection paths in the simulated environment. The second part is handling the audio rendering, producing the audible result of the simulation based on information given by the first part. This paper will focusing on the first part

Aircraft noise and speech intelligibility in an outdoor living space.

Studies of effects on speech intelligibility from aircraft noise in outdoor places are currently lacking. To explore these effects, first-order ambisonic recordings of aircraft noise were reproduced outdoors in a pergola. The average background level was 47 dB LA eq. Lists of phonetically balanced words (LAS max,word = 54 dB) were reproduced simultaneously with aircraft passage noise (LAS max,noise = 72-84 dB). Twenty individually tested listeners wrote down each presented word while seated in the pergola. The main results were (i) aircraft noise negatively affects speech intelligibility at sound pressure levels that exceed those of the speech sound (signal-to-noise ratio, S/N < 0), and (ii) the simple A-weighted S/N ratio was nearly as good an indicator of speech intelligibility as were two more advanced models, the Speech Intelligibility Index and Glasberg and Moores [J. Audio Eng. Soc. 53, 906-918 (2005)] partial loudness model. This suggests that any of these indicators is applicable for predicting effects of aircraft noise on speech intelligibility outdoors.