I'm looking to understand how to estimate the sound isolation capacity of a wall structure. With rising degree of detail will probably come an exponantial increase in complexity. I'm looking to start of, euhm,... gently. :shy: What I've gathered so far: -The impedance of the wall seems to take center stage -There's atleast two fundamental aspects of the wall that govern its sound isolating qualities: mass and rigidity, each dominant over the other in a different frequency range I've posted one of the equations I've tried to solve, hoping someone can shine a light. A plane wave of single frequency 200Hz travelling through air at 344m/s is obstructed by a single leaf gypsum board wall, 25mm thick, with infinite X and Y dimensions (some wall eh). Frequency f = 200Hz Thickness h = 0.025 m Young’s modulus E = 2,3*10^9 N/m² Poisson ratio V = 0,33 Mass M = 25 Kg/m² Speed of sound c = 344 m/s Angle of incidence φ = Perpendicular to boundary = 1/2π w = f * 2π = 200Hz * 2π = 400π Rigidity D = (E*h³)/(12*(1-V²)) = (2,3*10^9*0.025³)/(12*(1-0.33²)) = 3360,78 Z = M*w² (wall impedance as a result of its Mass) = 25*(400π)² = 39478417,6 => 20*LOG(39478417,6) = 151,93 dB Z = D*((w / c)*sinφ)^4 (wall impedance as a result of its Rigidity) = 3360,78*((200Hz*2π / 344)*sin (1/2π))^4 = 3360,78*(400π / 344)^4 = 598474,66 => 20*LOG(598474,66) = 115,54 dB My questions: 1) Are my numbers really off, or is it just me? 2) Assuming I get the impedance right, what would be the next step in determining the sound isolation quality of this idealized wall structure?