The proposal presented here addresses innovative approaches in the reproduction of audio signals mitigated by distortions in a room. The most significant phenomenon among the distortions is reverberation, a straightforward characterization of which is the room impulse response. Some of the promising research problems in acoustics are the creation of 3D audio and of multizone surround sound. Many techniques have been roposed in the literature for canceling or reducing the effect of reverberation on the signal. Impulse response inversion attempts to cancel the effect of reverberations whereas impulse response shortening is a technique for partly equalizing impulse responses. Shortening has less stringent constraints which can result in the creation of more practically realizable systems.

Room impulse responses used for the estimation of shortening filters are measured, hence easurement errors or noise could be present in them. In addition,room responses vary from time to time with changes in atmospheric conditions such as temperature and humidity and also due to change in positions inside a room. The design of a hortening filter that is robust to at least some of these variations is likely to be very useful. While empirical approaches for designing robust filters have been proposed, a more plausible approach would be statistical, involving the inclusion of some statistical constraints into the optimization problem.

The present research also aims at the development of a computationally efficient approach for RIR shortening. A preliminary work in this direction used a formulation similar to the Basis Pursuit DeNoising formulation (BPDN) used in sparse reconstruction, involving minimization of a combination of the l2 norm of the weighted error and an l1 regularizer. This was demonstrated to result in a computationally efficient approach that also guarantees good performance. Noting that the existing literature does not contain many efforts that have concentrated on the design of computationally efficient or robust shortening filters, the work proposed here appears to be worth pursuing.