In the sound engineering community there is debate about the sound quality of an audio mix that has been digitally summed instead of summed using an analogue mixing console. For the purpose of this paper, the terms "summing" and "mixing" will be used interchangeably and an "analogue" sample will refer to audio that has been summed in an analogue console, even if it played from a digital system. Some professionals say that a digital mix is lacking the "undeniable depth, width, punch and realism" of an analogue mix. However, as Leonard et al. states, there is not much "quantifiable evidence to support these claims" yet. And although others, like Cochrane, point out that summing with a digital audio workstation (DAW) or analogue console will not necessarily improve the quality of a song if it has not been correctly mixed (artistically speaking), it is generally accepted that the limitations of analogue equipment might account for the difference in the perceived character of the mix. For sound engineers who have been recording and mixing for the past 20 years, this unexplained variation of sound is a source of frustration, and summing boxes, like the Crane Song Egret or Rupert Neve Design 5059, are being sold for the sole purpose of creating an analogue mix.
The hypothesis for this thesis is that a mechanism to provide the characteristics of an analogue mixer can be found and implemented in a digital mix. The first goal of this project is to definitively prove whether a visual or audible difference in sound quality exists through visual and aural testing. The second objective is to design and implement an interface that facilitates user comparison of two audio samples. The user should also be able to control the mixing algorithm and other variables affecting the sound of a digitally summed mix using the interface. Lastly, it should be determined whether a digital mixing algorithm can be created to satisfactorily emulate the sound of a mix summed in an analogue console.