A Comparative Study of Analogue and Digital Mixing Techniques

The difference between the summing quality of analogue and digital audio is widely debated. There are claims stating that audio summed by an analogue console sounds warmer than audio that has been summed by a digital audio workstation (DAW). It was hypothesized that a mechanism to provide the characteristics of an analogue mixer could be found and implemented in a digital mix. The project therefore aimed to prove whether an audible or visual difference between summing techniques existed. Possible causes for this difference, such as sampling rates, frequency response in human hearing, panning laws and analogue equipment were considered. A study of how three open source digital audio workstations (DAWs) define and implement gain, panning and summing of individual samples was then discussed. Previous testing of DAWs and alternate methods for summing samples were also reviewed. An Audio Mix Analyzer was designed and implemented to facilitate the creation of audio tracks using various mixing algorithms, and to enable the comparison of two audio samples. Listening tests were performed using the Audio Mix Analyzer and summed sine waves were evaluated visually. Testing on the summing of an analogue mixing console was also performed. All participants could hear a difference between the analogue sum and the digitally-summed audio. This difference was dependent on the genre of the song and the number of tracks being summed. The digital algorithm that appeared to sound the most similar to analogue summing simply added audio samples together.