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

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A rigorous perceptual model for auditory perception is given by a psychologically
oriented localisation model that was proposed by PLENGE 1973. This model probably
offers a comprehensive explanation for inside-the-head locatedness (Figure 15).
It comprises both short- and long-term memory as well as a stimulus processing
mechanism that compares stored stimulus patterns to input patterns. The stimulus
processing does not lead to (externalised) localisation if (1) the short-term memory
does not contain or (still) contains wrong information about sound sources and their
locations or (2) the stimuli are of such a kind that “they cannot be mapped to a
stimulus pattern contained in long-term memory”.
Remarkably, in this model localisation is traced back to a learning process, the shortterm
as well as the long-term memory being of particular importance. The approach
“stimulus processing by means of comparison with stored stimulus patterns” is
contained in the association model. The “associatively guided pattern recognition” can
be seen as its further development.
3.2.2 The functioning of the association model
The above considerations lead to the following functional principle of the association
model (Figure 16).
Apart from the peripheral stage that subdivides the ear signals into spectral
components of approximately constant relative bandwidth with the help of filter banks
(see ZWICKER / FELDKELLER 1967, DUIFHUIS 1972, BLAUERT 1974, 1978),
the association model comprises the two central processing stages “location
association stage” and “gestalt association stage”. Each of these two processing
mechanisms takes place in the form of an associatively guided pattern selection.
Having passed the peripheral stage, certain ear signals give rise to a location
association in the first and to a gestalt association in the second, higher-level stage.
The two stages always determine the auditory event properties in a conjoint fashion.
The rigorous differentiation of these two stimulus evaluation stages corresponds
entirely to the two elementary areas of auditory experience. The received ear signals
can be attributed to the two sound source characteristics of “location” and “signal”,
which are independent of each other but always occur in a pairwise fashion.
In principle, the two central evaluation stages therefore also contain the same
processing mechanisms. Similar to the location association stage’s mechanism for
localisation stimulus selection that was outlined above, the gestalt association stage
contains a mechanism for the selection of the gestalt.