The technique of elevation filtering and phase shift processing to improve the audibility of sounds in mixing
Shanyu Xie · White Rose eTheses Online (University of Leeds, The University of Sheffield, University of York) · 2015
In the area of audio recording and reproduction, mixing is the process by which multiple sound sources (of either a recorded or synthetic origin) are combined, over one or more channels. However, when sound tracks are combined, mix engineers have to take care to preserve quality, as multiple sounds may occur at once. The more masking that occurs during mixing, the worse the audible sound quality. For this research project, I have chosen two methods to help improve audibility of sounds in the final mix. The first is elevation filtering. Elevation filtering is based on the theories of IID, ITD and pinna effect. I decided to design an elevation difference filter, which includes the elevation data. If we utilize such an elevation filter for a sound track, the perceived source position will change and allow it to be distinguished from other sounds. Another method is creating a 180 degree phase shift (out of phase) situation to reduce the level of masking. This technique is based on the theory of the binaural release of masking. Given that an out of phase situation can decrease masking, I have designed a Max/MSP patch which can create an ‘out of phase’ situation for two ears in any azimuth position. Finally, these two methods will be tested to see if the difference in sound quality is audible or not. A musical composition will also be created, utilizing these two technologies, which will constitute the musical outcome of my research.