Ambient listening

Another application was the "huddle." In an air traffic control tower, team members engage in ambient listening to maintain constant situational awareness of the everyday activity around them and scan for irregularities or potentially emerging risk. When conditions are detected that are moving them into zones of intolerable risk, workers stand up from their cubicles to establish critical communication with each... 

Headphones, unlike ambient listening conditions, offer a consistent and stable aural environment, do not normally affect others in the vicinity, and offer excellent sound quality at a far lower price than comparable loudspeaker systems. In-head localization is perhaps the greatest single obstacle to ubiquitous use of headphone systems. 

Figure 23-3. Permissible distance between a speaker and listeners for specified voice levels and ambient noise levels. The levels in parentheses refer to voice levels measured 1 m from the mouth. (From MIL-STD-1472G.)...

Note that spherical objects produce the most uniform frequency response. Also note that where 9 = 50° the most serious diffraction occurs. For the cylinder and cube this angle places a very sharp transition between the point of radiation and the measuring point at 0°. Since a variety of objects are found in most listening areas, even in recording studios, very careful design of the ambient monitoring environment is essential to transparent sound reproduction. See Fig. 3.43 (Eargle, 1994, 29). 

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