The best way to hear these recordings is through headphones, even inexpensive headphones, To really appreciate the "surround" effect, a pair of headphones with great stereo separation is necessary. Listeners will better sense the binaural effect by using open air headphones, instead of closed back headphones.
These recordings were captured using special head worn microphones, utilizing the head as a key tool for recording. This process is called the “Head Related Transfer Function” or “HRTF.” HRTF refers to the physical dimensions of the human head and how this impacts the mechanism of human hearing. Because of the physical separation of the ears on the human head, our ears have the capability of hearing in three dimensions. As sound waves reach the human head from a particular direction, they enter the ears at slightly different times. The brain is able to calculate these time differences resulting in a perception of direction within a field of three hundred sixty degrees around the head.
HRTF recording requires a “binaural” microphone system. This type of microphone system utilizes a baffle representative of the human head or the actual head of the recording artist. To make binaural recordings using the actual head requires placement of a tiny microphone inside each auditory canal of the phonographer’s ears. The most recognized binaural microphone of this type is the Neumann KU100, a system comprised of a “dummy” head with microphones in each ear. It is important to note that recordings made in this way have one drawback. In order to best hear three-dimensional sound, the resulting recording should be experienced through headphones. Although the stereo quality of the recording is exceptional, the three hundred sixty degree effect does not transfer well through conventional speakers.
An alternate technique for utilizing the HRTF in recording allows the user to wear microphones forward of the ears over the temples. This appratus is headphone-like, although to the casual observer, it appears as headphones or muffs. An example of this is Sonic Studios™ DSM™ microphone systems. This systems uses a patented method for achieving a type of binaural effect with the ability to hear the captured sound field on conventional speakers.