Replace the third paragraph beginning with "Determine total absorption..." with the following text:Determine the typical residual sound absorption factor (AR): Multiply theroom area by 15%. This factor accounts for the acoustically untreatedroom surfaces and for the furnishings. Determine total absorption (A) byadding the residual sound absorption factor (AR) and the absorption fromthe room materials: gypsum board walls on studs, linoleum floor, ordinarywindow glass, and acoustical ceiling tiles (NRC = 0.70; sound absorptioncoefficient at 500 Hz = 0.72, from manufacturer\'s data).500 Hz calculation data: