In order to investigate the effects of noise and reverberation on word intelligibility and on the listening difficulty in classrooms psychoacoustic experiments were performed using auralized sound fields. The rendering system is single user and consists in a 12 channels multi stereo dipole array implemented inside a silent room. The apparatus works with measured or simulated impulse responses, provides a quite natural listening experience and an extremely realistic spatial impression. Binaural impulse responses were measured with or without pupils present in two similar classrooms, one of them being acoustically treated. Also typical noise samples were recorded. Then auralized sound fields were prepared by digital mixing of speech and noise to cover a wide range of conditions. A Diagnostic Rhyme Test (DRT) was prepared in the Italian language. The 80 pupils and 42 adults participating in the tests had also to judge the difficulty on a 5 points scale. Firstly the relationship between intelligibility and STI showed that the requirements for pupils are more stringent that those in ISO9921. Secondly it was found that the listening difficulty does not always offer an advantage with respect to the intelligibility.
Speech intelligibility and listening difficulty tests in auralized classrooms by means of a multi-dipole rendering system
PRODI, Nicola;FARNETANI, Andrea;VISENTIN, Chiara;POMPOLI, Roberto
2009
Abstract
In order to investigate the effects of noise and reverberation on word intelligibility and on the listening difficulty in classrooms psychoacoustic experiments were performed using auralized sound fields. The rendering system is single user and consists in a 12 channels multi stereo dipole array implemented inside a silent room. The apparatus works with measured or simulated impulse responses, provides a quite natural listening experience and an extremely realistic spatial impression. Binaural impulse responses were measured with or without pupils present in two similar classrooms, one of them being acoustically treated. Also typical noise samples were recorded. Then auralized sound fields were prepared by digital mixing of speech and noise to cover a wide range of conditions. A Diagnostic Rhyme Test (DRT) was prepared in the Italian language. The 80 pupils and 42 adults participating in the tests had also to judge the difficulty on a 5 points scale. Firstly the relationship between intelligibility and STI showed that the requirements for pupils are more stringent that those in ISO9921. Secondly it was found that the listening difficulty does not always offer an advantage with respect to the intelligibility.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
