Other cues  

The human  outer ear  , i.e. the structures of
the  pinna  "Pinna \(anatomy\)") and the external 
ear canal  , form direction-selective filters.
Depending on the sound input direction, different filter resonances become
active. These resonances implant direction-specific patterns into the 
frequency responses  of the
ears, which can be evaluated by the  auditory system  for sound localization. Together with other direction-
selective reflections at the head, shoulders and torso, they form the outer
ear transfer functions. These patterns in the ear's  frequency responses
 are highly individual,
depending on the shape and size of the outer ear. If sound is presented
through headphones, and has been recorded via another head with different-
shaped outer ear surfaces, the directional patterns differ from the listener's
own, and problems will appear when trying to evaluate directions in the median
plane with these foreign ears. As a consequence, front–back permutations or
inside-the-head-localization can appear when listening to  dummy head
recordings  , or otherwise
referred to as binaural recordings. It has been shown that human subjects can
monaurally localize high frequency sound but not low frequency sound. Binaural
localization, however, was possible with lower frequencies. This is likely due
to the pinna being small enough to only interact with sound waves of high
frequency.  [18]  It seems that people can only accurately localize the
elevation of sounds that are complex and include frequencies above 7,000 Hz,
and a pinna must be present.  [19]

When the head is stationary, the binaural cues for lateral sound localization
(interaural time difference and interaural level difference) do not give
information about the location of a sound in the median plane. Identical ITDs
and ILDs can be produced by sounds at eye level or at any elevation, as long
as the lateral direction is constant. However, if the head is rotated, the ITD
and ILD change dynamically, and those changes are different for sounds at
different elevations. For example, if an eye-level sound source is straight
ahead and the head turns to the left, the sound becomes louder (and arrives
sooner) at the right ear than at the left. But if the sound source is directly
overhead, there will be no change in the ITD and ILD as the head turns.
Intermediate elevations will produce intermediate degrees of change, and if
the presentation of binaural cues to the two ears during head movement is
reversed, the sound will be heard behind the listener.  [13]  [20]   Hans
Wallach  [21]  artificially altered a
sound's binaural cues during movements of the head. Although the sound was
objectively placed at eye level, the dynamic changes to ITD and ILD as the
head rotated were those that would be produced if the sound source had been
elevated. In this situation, the sound was heard at the synthesized elevation.
The fact that the sound sources objectively remained at eye level prevented
monaural cues from specifying the elevation, showing that it was the dynamic
change in the binaural cues during head movement that allowed the sound to be
correctly localized in the vertical dimension. The head movements need not be
actively produced; accurate vertical localization occurred in a similar setup
when the head rotation was produced passively, by seating the blindfolded
subject in a rotating chair. As long as the dynamic changes in binaural cues
accompanied a perceived head rotation, the synthesized elevation was
perceived.  [13]

In the 1960s  Batteau 
showed the pinna also enhances horizontal localization.  [22]  [23]