Reproducing, and sometimes even exaggerating these effects can add a lot to realism of your VRML world, but to do this, you need to get creative with the VRML sound primitives. The first step in adding realism to your soundscape is to determine what effects will offer the most bang for the byte. Listen carefully to what happens in the real world when you walk from room to room. Another good source of ideas is the movie industry, as movie sound effects are often exagerated. Try to pinpoint the effect that you want to try to achieve.
Low frequencies tend to travel better through and around objects.
This leads to a muffled effect on sounds at a distance, or sounds behind walls or other obstacles, and bright, clear sounds when the listener is near the source. Echos in a cave or a mountain range are caused by sound reflecting off of the walls. Reproduce the effect The VRML sound primitives don't provide a means for achieving any of the effects we've just mentioned, so we'll ned to resort to other means for reproducing or approximating the effect we're after. Sound Editting software - There are a large number of tools on the Mac, PC's and SGI platforms which will allow you to filter and manipulate a sampled sound in a variety of ways. Many of these provide plugin interfaces so you can purchase additional filters and effects.