# Timbre Preferences in the Context of Mixing Music
## 4 Experimental Method  
For the experiment, participants (n = 28, age 18-70, median 24, male = 9, female = 18, other = 1, Goldsmith Music Sophistication Index (GMSI) 31-117, median 75, no professional sound engineers or music producers) were instructed to manipulate a series of musical loops, examples being available online, via a set of four sliders on a laptop in front of them. The loops, which played alongside a premade drum loop, were designed to roughly represent a prototype of a \"Bassline\", a \"Harmony\", which would also double as a type of melody, and an \"Arpeggio\", another type of melody, of a musical piece section. These loops were presented over headphones (Audio-Technica M50x) by the same laptop. A participant's task was to make the loop sound as good as possible to him or her, given their ability and preference. For this setup, an additive synthesizer was created in Max/MSP that was able to generate sounds consisting of a fundamental frequency and up to 275 harmonics. The harmonics were manipulable according to the FX established in Section 5. This synthesizer was able to play simple MIDI files in a loop and then record the resulting output into an audio file (44.1 kHz/16 bit, *.wav). Accompanying the MIDI loop was an audio loop with a pre-recorded drumbeat to give a more realistic musical context. Although adjusting the volume of the individual voices is usually one of the core aspects of music mixing, this option was purposely not given to the participants. Since the focus of this study was on timbre, with 50% of its entire definition being \"aspects of a sound, which are not loudness\", it would have been counterproductive to the aim of the experiment. Additionally, since louder sounds are generally preferred by listeners [24], a novice mixer often only increases the volume of all the voices, not paying attention to their timbre, ending up with just an overall louder mix. First, the participant adjusted the sound of the bassline, accompanied by the unchanging drum pattern. When the participant was satisfied with the result of their slider settings for the first \"bassline\" loop, they could click on a \"continue\" button, which caused the synthesizer to play through the loop once more and record the output into a separate audio file. In the next step, a second MIDI loop \"harmony\" would start to be played by the synthesizer, again manipulable by the four sliders. From the second repetition onwards, this MIDI loop was accompanied by the recorded audio of the \"bassline\" first loop. Again, the participant could mix this loop and record it to the computer when finished, which would trigger the third iteration of this process, now with the \"arpeggio\" loop, accompanied by both, bassline and harmony loops, as well as the drum loop. The process is visualized in Figure 2.  
This order of musical phrases was chosen to represent a common bottom-up mixing strategy in pop music, where an audio engineer would often mix in this order: that is, Drums, Bass, guitars/synths, vocals, and finally any extras. After this last loop, the entire process would start anew with a second set of looped phrases, until the participant had mixed a total of five looped musical pieces (although each such musical piece is only eight or sixteen bars). During the mixing phases, the participant was  
Figure 2: Representation of the process of part one of the experiment. MIDI = Musical Instrument Digital Interface. given the option of muting all the other audio loops with a \"SOLO\" button, singling out the presently manipulable MIDI loop, for a clearer understanding of the changes effected by the sliders on that musical phrase. The muted tracks could be unmounted with a \"FullMix\" button, which appeared instead of the \"SOLO\" button, when solo-mode was engaged. Whenever the participant was finished with mixing a phrase and clicked \"continue\", the final positions of the sliders for the given loop were recorded, as was the musical loop itself.