Active multichannel audio downmix

Mixing down signals of a multi-channel configuration into a format with fewer channels is widely used in many areas of audio coding, production and recording. Commonly used downmix methods are based on fixed downmix coefficients or mixing equations. Experience has shown that these passive methods cause quality losses in terms of speech intelligibility, vocal/instrumental clarity and timbre-changes. In this paper a novel method is introduced that addresses these problems. The method aims to preserve the energy of the input signals during the downmix. In doing so, magnitude and phase are retrieved from two different approaches and combined afterwards. A listening test was conducted. The results prove that the introduced method has a significant positive effect on the aforementioned quality aspects.