Question

1. Plot the transmission loss as a function of frequency between 100 Hz and 10 kHz for the following types of "walls": a) A sheet rock and stud wall, ?-20 kg/m2 b) A plaster, lath and stud wall. ?-60 kg/m2 c) A glass window, ?-8 kg/m d) A brick and plaster wall, o-450 kg/m2. e) A solid wood door, ?-35 kg/m2. f) A hollow core door, ?-5 kgm2 Calculate the transmission loss of a wall that is 9 m by 2.5 m and is built of brick but contains a closed glass window 0.7 m by l m. Use the data given in Problem I. Assume?100,500. 1k, and 2 kHz. What fraction of the total energy passing through the wall comes through the window? To obtain the transmission loss for this wall calculate the transmission loss for the brick and glass then power coming through each. The total power is then "averaged" over the entire wall and a transmission loss for the composite wall is obtained. 2.

Answer question 2

Answer 1

"Given that The transmission loss at a function of frequency between 100 HZ and following types of ""walls"" sheet rock and stud wall, sigma = 20 kg/m^2 the expression for transmission loss TL = 10 log (1 + (2 pi f 6s/2 sigma c)^2) consider the acoustic impedance of sheet rock and stud wall sigma c = 11 times 10^sigma kg/m^2 - sec substitute the values in above equation Tl = 10 log (1 + (2 pi f times 20/2 times 11 times 10^6)^2) = 10 log (1 + 0.3262 times 10^-10 f^2 transmission table loss versus frequency: \r\n A plaster, lath and stud wall, sigma = 60 kg/m^2 the expression for transmission loss Tl = 10 log (1 + (2 pi f sigma s/2 sigma c)^2) The acoustic impendence of sheet plaster hath and wall sigma c = 15 times 10^6 kg/m^2 - sec TL = 10 log (1 + 2 pi f times 60/2 times 15 times 10^6) = 10 "