Two numerical models are presented for the prediction of sound leakage thro
ugh openings in thin hard barriers. The first numerical method is based on
a simple procedure of numerical integration that can be implemented straigh
tforwardly. This model is a more general approach, suitable for barriers wi
th arbitrary gaps. The second model is a new method that permits prediction
of sound leakage due to the presence of horizontal gaps in a long barrier.
In the new method, effective barriers of appropriate heights represent the
edges of the horizontal gaps. The sound diffracted by each effective barri
er is calculated by a closed-form analytic expression. The total sound-pres
sure level is determined from a sum of these diffracted fields. Hence, the
new method is fast, simple, and intuitive, allowing the leakage to be asses
sed accurately. The validity of these two numerical models is confirmed by
precise experimental measurements. (C) 2001 Acoustical Society of America.