Environmental Modeling Environmental cues, such as early echoes and dense reverberation, are important for a realistic listening experience and are known to improve localization and externalization of audio sources. However, by borrowing statistical techniques from the field of architectural acoustics researchers are developing cost-effective methods for approximating the effects of listening environments. Headphones Existing spatial audio systems are designed for use via headphones. This requirement may result in certain limitations on their use. For example, spatial audio may be limited to those applications for which a user is already wearing some sort of headgear, or for which the advantages of spatial sound outweigh the inconvenience of a headset.
Headphones also eliminate crosstalk between the binaural signals.
With additional signal processing, we can conceivably compensate for these effects, allowing spatial audio to be presented over free field speakers. Without head tracking, we cannot produce true 3-dimensional spatial sound in any practical way. Furthermore, when systems do not perform effectively, developers are often at a loss to explain why. Furthermore, it is entirely possible that other, presently unknown cues may be of great importance. Fortunately, human factors psychologists around the world are constantly improving our understanding of auditory localization.