Spatial unmasking and attention related to the cocktail party problem

Abstract

Although there are several factors causing ''cocktail party effect'' after more than half a century of research, the major one is considered to be the spatial separation of the target signal and the interferer. This paper will overview developments of the improvement of performance resulting from the directional separation of the target signal from interferers when listening in a field or through headphones. The basic assumption concerning the cocktail party effect is that there are one or more interfering sound sources in addition to the target signal source. In this situation it is important to remember the selective attention effect, which attenuates the interfering sound by concentrating the attention on a specific signal. Pitch of sound is the simplest cue for selective attention; however, spatial information can also be one. The latter half of this review discusses the effect of spatial filtering and an attention filter on the frequency domain.

Measurement of the laterality threshold of a tone with an interaural intensity difference under temporal masking conditions

“…This result provides a strong contrast with our previous experiment [1] using the tones with Fig. 4 The detection threshold and the laterality threshold.…”

“…In the previous studies, the laterality threshold was mainly investigated using a tone with an interaural time difference (ITD) [1], and there are few studies on laterality using interaural intensity differences (IID). In these studies using IIDs, a click or noise is usually employed as a stimulus [2][3][4][5][6].…”

Some spatial and temporal effects on the speech privacy of meeting rooms

“…6,7 In the initial work 2 subjects listened in approximately free-field conditions. The speech sounds arrived from a loudspeaker system directly in front of the seated subject and the noise sounds arrived from another loudspeaker system directly overhead.…”

“…Our knowledge of the effects of the spatial separation of speech and noise sources is almost entirely based on the perception of only the direct sounds in free-field conditions. 6,7 It is quite possible that the addition of reflected sound to the speech and noise signals considerably modifies these effects.…”

“…5 There have been at least two reviews of the many studies related to the cocktail party effect. 6,7 Interfering sounds can mask the target speech sounds ͑that we wish to hear͒ and reduce the intelligibility of the speech. The intelligibility of speech is first a SNR issue and the work of French and Steinberg, 8 which led to the articulation index, can explain the monaural signal-to-noise effects on speech intelligibility.…”