on the localisation in the superimposed soundfield - Hauptmikrofon ...

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DURLACH 1963, 1972 or the “correlation model” by OSMAN 1971) therefore
follow the location association stage.
The model for pitch perception of complex sounds by TERHARDT 1972 agrees
especially well with the associative processing of the gestalt association stage. It is
based on the assumption that
“… the human hearing system does not inherently know the difference between
harmonic and non-harmonic sounds. If the hearing system is ‘in a natural state’,
every sound is made up of a complicated combination of spectral pitches and
perceived sound pressure fluctuations. … With the help of acquired knowledge
of pitch relations between harmonically related sounds and the perceived
frequency of the sound pressure fluctuations, the hearing system allocates a tonal
meaning to each presented sound. This tonal meaning is perceived more or less
distinctively as ‘virtual pitch’.” (TERHARDT 1972)
The association model is compatible with this model, too. The source signals, which
are discriminated by the effect of the location association stage, contain all spectral
information. The perception (see definition on page 29) of sound colour can occur in
terms of both proposed models.
At this point, a localisation phenomenon shall be pointed out that so far has not been
explicitly investigated. The sound colour of an auditory event turns out to be largely
independent of the location of a sound event, even though the spectra of the ear
signals are strongly location-dependent (e.g. see BLAUERT 1974). To illustrate, a
listener slowly turning by 180° in front of a loudspeaker that is located in an anechoic
chamber and that radiates white noise hardly perceives changes in sound colour when
listening binaurally.
This phenomenon can easily be explained by means of the effect of the location
association stage. As a result of the localisation stimulus selection, only the
discriminated source signal reaches the gestalt association stage. It is not until here
that the process for determining sound colour takes place.
What effect does the model have in the superimposed sound field? To begin with, this
shall be illustrated for the phantom source situation.
A useful way of depicting the effect is by means of “impulse diagrams”, which depict
the temporal, binaural characteristics in a simple manner. The well-known hypothesis
that the auditory system initially evaluates each ear signal similar to an autocorrelation
analysis (e.g. LICKLIDER 1951) but separately for narrow frequency
bands (e.g. ZWICKER / FELDKELLER 1967, DUIFHUIS 1972, BLAUERT 1974,
1978) justifies this illustration method. The relative positions of the maxima reflect
the interaural time difference for each frequency band (see Section 4.1). For the