Optimized gradient calculation for room impulse response reshaping algorithm based on p-norm optimization

By using room impulse response shortening and reshaping it is possible to reduce the reverberation effects and therefore improve the perceived quality. This may be achieved by a prefilter that modifies the overall impulse response to have a faster decay. The traditional filter shortening approach using least-squares methods is fast and directly computable, but it suffers from late echoes. Newer approaches using the p-norm overcome this drawback but are computationally very demanding, as the optimization process uses a gradient-descent approach with slow convergence. In this work we propose a modification to this approach that results in a significantly faster convergence. With this modification, the algorithm is less likely to be trapped in a local minimum and therefore also leads to a better convergence point. The method will be demonstrated on simulated and real-world room impulse responses.