This page has a small sample of improvements in version 5.x that are Audio Engine related..
Solo and Mutes:
you can now Solo and Mute individual channels that transfer to newly created files the same as you hear them! No longer do you have to wait to Extract a channel to hear it by it's lonesome to figure out if it's the channel you were looking for.
Solo or Mute away now just like any mixing desk. When you find the channel you are looking for Tag it, Copy it or Spot It!
Field Recorder Detection and Down mixing:
5.x has many improvements for field record files regarding importing and playback. Once such audio improvement is....
When BH detects a possible field record file it will audition it down mixed to stereo if it has more then 2 channels and you are in a 5.1 or 7.1 environment.
NOTE: You can also force a down mix in any files by putting "F/R" in the [microphone] field
Auto Toggle M/S Decoder:
when turned ON from the Option page (see left) and a file has "M/S" in the [microphone] file it will auto-toggle the M/S Decoder ON/Off for you so you don't have to manually do it still.
(See image to the right)