Abstract: An audio apparatus extracts information of a musical performance from an acoustic signal having a frequency and an amplitude, which time-vary during the musical performance. In the audio apparatus, a filtering device has a plurality of filters which are set with different cutoff frequencies so as to pass different frequency ranges of the acoustic signal. A pitch detecting device is connected to the filtering device for processing the acoustic signal to detect therefrom a pitch. A controlling device operates according to the detected pitch fed back from the pitch detecting device for selecting one of the filters set with one of the different cutoff frequencies adapted to the pitch of the acoustic signal so that the pitch detecting device can detect the pitch based on the acoustic signal filtered by the selected filter. Further, the envelope detecting device has a plurality of envelope followers corresponding to the plurality of the filters.

Abstract: A signal analysis device for determining the pitch of a plucked string in which propagation times of plucking transients are evaluated to determine pitch. A neural network may be employed to perform evaluation based upon groups of pulses.

Abstract: A method is specified for pitch recognition, in particular for musical instruments which are excited by plucking or striking, in the case of which method the interval between zero crossings of a signal waveform of an audio signal is used as a measure for the period length of the audio signal.Reliable pitch recognition is intended to be possible in a simple manner using such a method. The method is intended to be capable of being implemented with a low level of computation power.To this end, the magnitude of the gradient of the signal waveform is in each case determined in the region of its zero crossings, and the magnitude of the gradient is used as an assessment criterion for the selection of the zero crossings to be evaluated.