Brief Communication: The Prevalence of High Intake of Vitamin E From the Use of Supplements Among U.S. Adults

Abstract

Intelligibility is the key factor in speech communication. Reverberation or surrounding noise is an adverse condition to the intelligibility from an acoustical perspective. Reverberation effects on the intelligibility can be characterized by the ratio of the direct energy to its reverberant energy, which depends on the distance from the source (or talker). The direct sound, from a perceptual perspective, may be extended into a superposition of the direct and following early echoes within around 30(ms) after the direct echo. These early echoes may help increase the direct sound, even under reverberant conditions, rather than decrease intelligibility due to reflected sounds. On the other hand, the intelligibility is conveyed in the narrowband envelopes (around 1/4−octave band). Assuming a reverberant space to be a linear system of sound wave transmission, the modulation index (or spectral magnitude) of a modulated sound decreases due to transmission through reverberant space. The decrease in the modulation index decreases the intelligibility as the sound source distance increases. Effects of sound absorption or arrays of sound sources on the intelligibility are illustrated by increasing the energy ratio. The arrangement of sound absorbers that creates steep initial slopes of the reverberation decay curves implies the possibility of designing an auditorium that combines intelligible speech with rich reverberation of music.