1. Divide the duct area by two or more until you finda comparable duct area, and then multiply the throw by 1.4, this is a common constant for the adjustment in total air mass that is used for extrapolating throw performance. This conversion factor is also used in all of the linear diffuser conversion charts.
2. A good rule of thumb on sound is to increase the sound data by 3 NC to obtain a cumulative value.
Mark Costello - GRD Product Manager