Study of the Effect of Reverberation and Amplification on Sound Localization - Essay Example

Reverberation is defined as the combined effect of multiple sound reflections within a room. The reverberation characteristics of a room are affected by several factors: (a) the shape and size of the room, (b) the materials of which the room is constructed, and (c) the materials present, which are especially important since they determine how much sound is absorbed and how much is reflected. When sound bounces off surfaces, it creates echoes of the original signal, and these may be slightly different from the original signal in terms of frequency and temporal cues.

Echoes also provide reflection cues that might be useful in localization. The ratio of the direct sound arriving at the listener’s ear, to the reflected sound, can be used as a cue for localization in unfamiliar environments (Moore, 2003). Early reflections are more easily localized than late ones, as our ears are sensitive to the arrival times and decreasing amplitudes of early reflections. On the other hand, late reflections tend to fuse and create a quality of sound diffusion or spreading and our brains can no longer distinguish the arrival times or intensities of individual reflections The human auditory system uses binaural and monaural spectral cues to process sound.

Studies of directional localization in rooms generally show that the effect of reverberation on localization accuracy is not very large, at least when onset information is available to the listener (Durlach et al., 2003). Reverberation physically distorts directional cues such as inter-aural differences, and there is some evidence that more realistic reverberation interferes with directional perception (Kidd, Mason, & Arbogast, 2005). Previous work shows that reverberation actually helps listeners judge source distance since judgments of distance are thought to depend on the ratio of direct to reverberant sound energy, in that the level of the direct sound is inversely proportional to the square of the source distance, while the level of reverberation is roughly independent of the source location.