Separating a signal from a competing noise location aids detection beyond diotic summation

Evidence

Sound localization indeed is a primary function of the auditory system, but perhaps more important for the daily life of modern people is the ability of the binaural system to functionally reduce the effects of noise on listening. We saw earlier in this chapter that having two ears can assist a person when detecting sounds in noise, but the effect was an improvement of 3 dB or less. A characteristic of these binaural summation studies is the diotic presentation of sound. Essentially, these experiments mimicked a situation where a signal and noise are originating from the same location in front of the body (i.e., they had a 0-ms ITD and a 0-dB ILD). However, in the section on sound localization, we saw that the perception of different locations requires different signals presented to each ear. Such cases reflect dichotic presentation of sound. The diotic situation is rarely encountered in daily life, as each ear commonly receives different signals, even if only slightly different between the two ears. In these cases, our binaural system plays an important role in allowing us to better detect (or understand) a signal when it is not co-located with a noise. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1540

Categorization

• DEFINE: Defines diotic versus dichotic presentation and states why real-life listening is dichotic.
• SHARE: Worth sending to an audiologist or audiology student learning how the binaural system functions in real listening rather than lab diotic tests.