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Psychoacoustics is the branch of psychophysics involving the scientific study of the perception of sound by the human auditory system.It is the branch of science studying the psychological responses associated with sound including noise, speech, and music.
The psychoacoustic model looks at the energy in each of these subbands, as well as in the original signal, and computes masking thresholds using psychoacoustic information. Each of the subband samples are quantized and encoded so as to keep the quantization noise below the dynamically computed masking threshold.
The greatest masking is when the masker and the signal are the same frequency and this decreases as the signal frequency moves further away from the masker frequency. [1] This phenomenon is called on-frequency masking and occurs because the masker and signal are within the same auditory filter (Figure C).
The psychoacoustic model analyzes the samples sent to it by the filter band, computing the masking threshold in each frequency band using a Fast Fourier transform. The number of points used depends upon the MPEG layer. Using these thresholds, the signal-to-mask ratio is determined and sent to the quantifier.
Psychoacoustic tuning curves can be measured using the notched-noise method. This form of measurement can take a considerable amount of time and can take around 30 minutes to find each masked threshold. [10] In the notched-noise method the subject is presented with a notched noise as the masker and a sinusoid (pure tone) as the signal.
Temporal envelope (ENV) and temporal fine structure (TFS) are changes in the amplitude and frequency of sound perceived by humans over time. These temporal changes are responsible for several aspects of auditory perception, including loudness, pitch and timbre perception and spatial hearing.
The precedence effect or law of the first wavefront is a binaural psychoacoustical effect concerning sound reflection and the perception of echoes.When two versions of the same sound presented are separated by a sufficiently short time delay (below the listener's echo threshold), listeners perceive a single auditory event; its perceived spatial location is dominated by the location of the ...
The next image represents a simple block diagram of the relationship between the human audio system and an objective psychoacoustic model. thumbs. From the model comparison of the test signal with the (original) reference signal, a number of model output variables are derived. Each model output variable may measure different psychoacoustic ...