Signal, Sound & Perception: A List of Variables

.

 

Not sure if I completely understand the topic.

Talking about sound, Frequency Response is definitely something to care for.
It's a pretty complex topic due to the great variety of recordings and listening habits.

 

Some bits on perception:

The brain makes use of phase/time differences, level differences, and coloration (HRTF) caused by the head and torso to the sound waves to determine sound source.

Most of these difference cues disappear when the sound source is directly in front, above, or behind you, besides the direction dependent coloration. It proves more difficult for a person to localize a sound on this median plane without turning their heads to introduce a difference between the ears. It is not impossible to locate either; there is still at least one cue left in coloration, and most people definitely lack symmetric ears.

Following from the idea that frequency response dictates position on the median plane, you can boost and null certain frequency bands to create or enhance an artificial sense of direction (up, down, front, back). This applies to the non-flat frequency response of the headphone.


I'll list some resources here, partly for my own reference.

If the end goal is to modify a headphone, Carl Poldy's publications on headphone acoustics would be useful.
First, the AES tutorial:
http://xenona.com/xenonaupl/Ivo_Hristev/AES-tutorials/aesTutorial48.pdf
He also wrote a chapter in the Loudspeaker and Headphone Handbook. One chapter, but it goes on for a hundred pages out of a seven hundred page book.
https://docs.google.com/file/d/0B_l73GVBBlIUNzg4ZmExODgtNDBkOS00YzI0LTg4NmUtZjFlMGMzMDA1NzY2/edit

Henrik Møller's overview of binaural perception and technique. The gear has changed over the decades and more research on binaural has since been conducted, but the core ideas have been generally stable.
http://vbn.aau.dk/files/54564101/Moller_1992.pdf