Timbral aspects of reproduced sound in small rooms. I

This paper reports some of the influences of individual reflections on the timbre of reproduced sound. A single loudspeaker with frequency-independent directivity characteristics, positioned in a listening room of normal size with frequency-independent absorption coefficients of the room surfaces, has been simulated using an electroacoustic setup.

The model included the direct sound, 17 individual reflections, and the reverberant field. The threshold of detection and just-noticeable differences for an increase in level were measured for individual reflections using eight subjects for noise and speech. The results have shown that the first-order floor and ceiling reflections are likely to individually contribute to the timbre of reproduced speech.

For a noise signal, additional reflections from the left sidewall will contribute individually. The level of the reverberant field has been found to have an effect on the contribution of the individual reflections. An increase in the level of individual reflections are most likely to be audible for the first-order floor and ceiling reflections, and certain reflections from the sidewalls.