Perceived intensity, measurement over

Exposure to a flavor over time always results in a decrease in the perceived intensity. This dynamic effect of flavorants, called adaptation, is a central part of the process by which people experience flavors in foods as well as in sensory tests. Measuring the dynamics of flavor perception is an emerging technology made possible by inexpensive computing. Called time-intensity analysis, these methods are finding wide appHcations in taste analysis. 

Human hearing is sensitive to sound frequencies from approximately 16 to 20,000 Hz and is most sensitive at 1000 Hz. At this frequency, a threshold root-mean-square pressure of 20 Pa (200 bar) can be perceived by normally hearing young adults under laboratory conditions. Sound pressure level (SPL) is measured in decibels relative to this threshold. Some approximate benchmarks for sound intensity are a whisper at 1 m (30 dB), normal conversion at 1 m (60 dB), and a subway train at 6 m (90 dB). Sounds increasing from 100 to 140 dB become uncomfortable and painful, and short exposures to a 160-dB level can cause permanent hearing impairment, while continuous exposme to sound levels over 90 dB can cause slow, cumulative damage [Sataloff et al., 1980]. 

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