Empirical corrections for predicting the sound insulation of double leaf cavity stud building elements with stiffer studs

Abstract

The experimentally determined normal incident mass-air-mass resonance frequency for a double leaf cavity stud building element is significantly greater than the theoretically predicted frequency for wood studs and steel studs manufactured from thicker sheet steel. This paper gives a method for calculating the effective mass-air-mass resonance frequency as the root mean square sum of the mass-air-mass resonance frequency and the resonance frequency of the first bending wave mode of the leaves between the studs. This calculation should use the isothermal mass-air-mass resonance frequency if the building element cavity contains porous sound absorbing material. If the cavity does not contain porous sound absorbing material, the usual adiabatic mass-air-mass resonance frequency should be used in the calculation. Because the exact boundary conditions of the building element leaves at the studs and the effective in situ damping are unknown, the paper gives empirical correction factors to determine the actual resonance frequency and the depth of the dip in the predicted sound insulation. This paper also gives empirically derived formulae for the line and point equivalent translational compliances of steel studs manufactured from different sheet steel gauges and compares them with formulae derived by other authors for the case of 25 gauge steel studs.

A review of the different approaches to predict the sound transmission loss of building partitions

“…An increase in the mass-air-mass resonance frequency was theoretically predicted by Lin and Garrelick 68 and experimentally observed by Bradley and Birta 69 in the laboratory although not in the field. Davy et al 70 have recently explained that the increase in the mass-air-mass angular resonance frequency in two leaf cavity stud walls is due to the spring of the air in the wall cavity coupling, not the masses per unit area of the wall leaves, but the drum modes of the wall leaves between the studs. Other approaches can be found in the literature to compute structure-borne sound transmission through the mechanical connections of double-leaf partitions, which cannot all be described in detail in this article.…”

The Acoustic Effect of Windows Installed in a Wood Frame Façade

“…The acoustic performance of the opaque wall, in turn, depends on its main structure (Bradley, Birta, 2001;Davy et al, 2019) but also largely on various details, dividers, and connections (Quirt et al, 1992;Ljunggren, Ågren, 2011). The installation of a window modifies the structural scheme of the wall as the studs, faces, and other elements are partly removed.…”

Pilot study on numerical prediction of sound reduction index of double window system: Comparison of finite element prediction method with measurement

“…However, they have various limitations in predicting the sound insulation mechanisms of existing windows, such as modeling under fixed conditions, panel size effects, and sound-incidence conditions. Therefore, theoretical predictions are sometimes insufficient for obtaining accurate prediction, although continuous efforts [12][13][14] are still being made to increase the prediction accuracy. Numerical analysis enables us to model the detailed conditions crucial for modeling real windows.…”