Download Realtime Control of Audio Effects Many sound processing effects need or can benefit from realtime control of one or more parameters. During interaction with the processor optimum settings can be achieved, or settings can be signal dependent. Time variance is a keyword here. For some effects the routing and mapping of the controller signals is of higher complexity than the audio signal routing itself. A concept for controlling a collection of effect blocks in real time with direct user interaction, and including controllers derived from the signal itself, is presented. This consists of a hierarchy of physical controllers, logical controllers, connection matrix, mapping functions, and effect parameters. And below that an effect parameter often controls several parameters in the signal processing algorithm. One controller can control more than one parameter and the mapping function from controller to the parameter can be set individually. Making this very flexible system easy to use presents some interesting challenges for the user interface design. Furthermore, as control signals can be derived from the audio signal itself, the signal processor has to calculate parameters from controller settings to a much higher extent than typically done, when a host processor takes care of this. The concept has been implemented in commercially available stand-alone effects processors.
Download Measuring Sensory Consonance by Auditory Modeling A current model of pitch perception is based on cochlear filtering followed by a periodicity detection. Such a computational model is implemented and then extended to characterise the sensory consonance of pitch intervals. A simple scalar measure of sensory consonance is developed, and to evaluate this perceptually related feature extraction the consonance is computed for musical intervals. The relation of consonance and dissonance to the psychoacoustic notions of roughness and critical bandwidth is discussed.
Download Real-Time Visualisation of Loudness Along Different Time Scales We propose a set of design criteria for visualising loudness features of an audio signal, measured along different time scales. A novel real-time loudness meter, based on these criteria, is presented. The meter simultaneously shows short-term loudness, long-term loudness and peak level. The short-term loudness is displayed using a circular bar graph. The meter displays the longterm loudness by means of a circular envelope graph, organized according to an absolute time-scale – looking similar to a radar display. Typically, the loudness measured during the past hour is visible. The algorithms underlying the meter's loudness and peak level measurements take into account recent ITU-R recommendations and research into loudness modelling.