A model of live performance is presented that includes simplified acoustic-environmental system models and enables the coupling behavior between multiple sources and receivers to be predicted. The model allows the mix at each location within the performance space to be evaluated as a function of the acoustic signals generated by the instruments and of the control parameters on the mixing desk, through which the instrument signals are sent before being reinforced using loudspeakers. For a set of listener locations, which includes both performers and members of the audience, ideal mixes are defined, and an optimization algorithm is developed that sets the control parameters on the mixing desk automatically, to deliver approximations of these ideal mixes to all listener locations simultaneously. The control parameters are constrained during the optimization to prevent the onset of acoustic feedback. The algorithm is examined, and we show that a targeted approach, which first sets the control parameters relating the vocal level, gives a better solution in a shorter time when compared to a brute-force approach.

The transient modifier is a type of audio effect that changes the level of the transient parts in a musical signal while leaving the steady-state parts unchanged. This article presents a high-performance algorithm for transient detection and modification, one that is capable of modifying transients in polyphonic or multi-voiced signals, and capable of modifying both hard (percussive) and soft (non-percussive) transients. The detection and modification of transients are performed in the frequency-domain using a sub-band approach. Detection is based on both phase and energy information using an adaptive threshold, and modification is carried out independently at each sub-band. The performance of the proposed sub-band approach was compared with other transient-modification algorithms using subjective listening tests. We show that the sub-band approach with adaptive threshold mostly outperforms other approaches.