Simulation of a pressure field developed by a song
For a perfect isotropic point source the pressure or air displacement at a point is just the pressure/displacement stimulating signal delayed by the time it took the disturbance to travel to that point. 

That means you get spherical shells of constant displacement, and the displacement is the signal at the time $t-d/c$ where $d$ is the distance from the source and $c$ is the propagation speed.

Addendum:

If you do not require the full resolution of the pressure field that would allow you to actually reconstruct the sound from the field then you may want to average the pressure over spatial volumes of constant size. That is not equivalent to a time average of the power, because the influence of spatial coarse graining on the pressure history depends on where you are. Only in the far field where the radius of the constant pressure sphere is much larger than the typical coarse graining scale, time averaging ans spatial averaging become equivalent.

So it depends on what you want exactly and what you need it for. The physics involved is very simple for a perfect point source, but gets very complicated as soon as you have participating objects. Maybe you can give a more detailed description of what you are trying to achieve with this.