Acoustic+vocabulary

=__**Acoustic words.**__=



Ceiling Attenuation Class (CAC) Single value for the laboratory sound attenuation of a suspended ceiling between two rooms according to ASTM E 1414. This measurement takes only into account the sound transmission through the suspended ceiling.  Rapid Speech Transmission Index (RASTI) RASTI is an objective way of measuring speech intelligibility. It is measured at two frequencies, 500 and 2000 Hz, by placing a loudspeaker, which transmits sound from the location of the person speaking, and a microphone where the listeners are situated. (See also STI).

Sound insulation The ability of a building element or building structure to reduce the sound transmission through it. The sound insulation is measured at different frequencies, normally 100-3150 Hz. Airborne sound insulation is expressed by a single value, //D//n,c,w, //R//w or //R'//w. Impact sound insulation is expressed by a single value //L//n,w or //L'// n,w.

Speech Transmission Index (STI) Similar to the RASTI method but a more complete form of measuring speech intelligibility by measuring all octave bands in the frequency range 125-8000 Hz.