Acoustical design of façade elements is a key element in architectural acoustics. The assessment is required for multi-family housing projects and environmental projects. In the 1980s, when labs around the US were measuring the transmission loss (TL) of exterior façade elements, it was assumed that measurement of TL with a diffuse sound field method is valid for TL of real facades where a diffuse sound field does not exist. Jerry evaluated how the TL of exterior façade elements change based on the incident angle. In this talk, we will shed some light on the history of the work done by Jerry in the advancement of the exterior façade assessment methods.