XBass, XBass II and 3D/3D+ are all analogue domain processing (ASP). We generally prefer to use analogue systems for volume, frequency response corrections and any other processing.
XBass/XBass II are frequency response corrections aimed at headphones and/or speakers depending on the product, so they adjust frequency response. On the xCan specifically XBass II offers a frequency response correction in the bass and lower mid-range (presence region of music) that takes a “typical” open back diffuse field tuned headphone (e.g. most modern European ones) and corrects them broadly for the Olive/Welti Frequency response target, with the option to skip the bass compensation for headphones with an elevated bass response and to skip the mid-range compensation for headphones where the mid-range region is already emphasized (many far eastern ones).
3D/3D+ is not operating by altering frequency response. It is often erroneously attributed as “crossfeed” and while it is true that it in effect processes the “difference” signal between left/right channels (like other similar systems) it is not traditional Bauer/Linkwitz crossfeed or Meier enhanced crossfeed (or any of the other published systems based on the same research and targets, be they analogue implementations of DSP). The iFi 3D/3D+ is a separate system to reduce “in head localisation” and to present a more natural, speaker like soundscape. It is based on very different targets derived in large scale listening tests back in the 1980s in what was then East Germany, far in advance of anything published previously and up to now elsewhere. The results are distinct from and well in advance of “Crossfeed” of all variants.
