Senior audio team member Ondřej Matějka goes over the details:
We’ve added a so-called limiter effect. If there are a large number of shots at the same time, there was an unpleasant effect of 'cracking'. The limiter should help counter this eventually.
We’ve changed the audibility of some sounds based on distance. Due to the changes to the sound engine it is now possible to affect the sound very accurately. As example, by separating the samples for weapon shooting and their mechanical parts, you can now not as easily hear the shooter in a remote area. With this change, the player also gets a better sense of ambient sound, because e.g. crickets are now heard only in a limited space. Another big change is the accurate setting of the volume of resources (dB) and controlling the audio mix (vehicles versus weapons for example). Rather than tweaking volume and loudness in the source samples, these are now all normalized and tweaking is done in configuration.
Finally, we’ve introduced an improved WSS format. With this change we can drastically reduce the size of the sounds by more than 60 percent and format WSS finally supports stereo samples.
Of course, there have been many fixes and tweaks to sounds themselves based on your comments. Please help our audio team by continuing to report possible improvements in this field.