VS1053B Datasheet, PDF (35/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC

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VS1053B
8. FUNCTIONAL DESCRIPTION
8.4 EarSpeaker Spatial Processing
While listening to headphones the sound has a tendency to be localized inside the head. The sound field
becomes flat and lacking the sensation of dimensions. This is an unnatural, awkward and sometimes
even disturbing situation. This phenomenon is often referred in literature as ‘lateralization’, meaning
’in-the-head’ localization. Long-term listening to lateralized sound may lead to listening fatigue.
All real-life sound sources are external, leaving traces to the acoustic wavefront that arrives to the ear
drums. From these traces, the auditory system of the brain is able to judge the distance and angle of each
sound source. In loudspeaker listening the sound is external and these traces are available. In headphone
listening these traces are missing or ambiguous.
EarSpeaker processes sound to make listening via headphones more like listening to the same music
from real loudspeakers or live music. Once EarSpeaker processing is activated, the instruments are
moved from inside to the outside of the head, making it easier to separate the different instruments (see
figure 14). The listening experience becomes more natural and pleasant, and the stereo image is sharper
as the instruments are widely on front of the listener instead of being inside the head.
Figure 14: EarSpeaker externalized sound sources vs. normal inside-the-head sound
Note that EarSpeaker differs from any common spatial processing effects, such as echo, reverb, or bass
boost. EarSpeaker accurately simulates the human auditory model and real listening environment acous-
tics. Thus is does not change the tonal character of the music by introducing artificial effects.
EarSpeaker processing can be parameterized to a few different modes, each simulating a little different
type of acoustical situation, suiting different personal preferences and types of recording. See section
8.7.1 for how to activate different modes.
• Off: Best option when listening through loudspeakers or if the audio to be played contains binaural
preprocessing.
• minimal: Suited for listening to normal musical scores with headphones, very subtle.
• normal: Suited for listening to normal musical scores with headphones, moves sound source fur-
ther away than minimal.
• extreme: Suited for old or ’dry’ recordings, or if the audio to be played is artificial, for example
generated MIDI.
Version 0.5, 2007-12-03
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