Adding air absorption to simulated room acoustic models

Room acoustics models are often used in auditory research. The simplest implementations of these models ignore air absorption, and this lack can affect the room response, especially at high frequencies and for large simulated spaces. This letter proposes a method for adding air absorption to a simulated room impulse response calculated without air absorption. The procedure creates a time-varying lowpass filter that approximates air absorption as a function of distance. The existing absorption-free room response is passed through the filter to create a new response that incorporates air absorption effects.