The latest sample sets of Sonus Paradisi are 6 channel surround. In addition to the front channels and rear channels, there are two more channels containing the near field direct pipe sound.
These extra two channels were recorded close to the pipes. Hence, they are named "Front direct" in the ODF.
The channels can be mixed arbitrarily to obtain wide range of virtual listening positions. To facilitate the process, the sample sets have special Mixer screen. The use of the mixer is best explained by the illustration: