**6. Conclusion**

Our research contributions that concur to show the potential of dynamic and static binaural monitoring solutions in enhancing performers' immersion in creative cognition are threefold. First, we constructed new theoretical knowledge on musicians' experiences when performing with headphones based on a multidisciplinary literature review and on survey responses from professional orchestra conductors and music improvisers. This knowledge provides acousticians with important insights to develop ecologically valid experimental protocols to assess innovative technologies in professional music performance contexts. Second, we designed one AMR and two AAR binaural monitoring solutions for which we detailed how we adapted their augmentation type, sound capture, and mixing approaches to distinct music performance contexts. Sound engineers can extend and modify these solutions to other contexts, within and beyond music performance. Third, we explored mixedmethod approaches to assess our technologies in three different professional performance contexts through eight case studies. These approaches combined performers' feedback on their experience by comparing binaural versus stereo conditions, their choice of takes, and the measurement of click-to-music loudness ratios in both conditions. Discussed in terms of performers' listening comfort, their perception of a realistic auditory scene, and their musical expression and creativity, our case study outcomes could be integrated into close-ended feedback questionnaire in future studies that aim at assessing monitoring solutions based on performers' experience.

Because this series of studies drew out more insights into the positive influence of using binaural headphone monitoring for instrumentalists than for conductors, future comparisons between the two AAR solutions, namely BHT and ABH, will be pursued with professional conductors to determine which dynamic binaural solutions could best support their performance experience. Because our case study outcomes underline the positive influence of binaural monitoring over the music performance for instrumentalists but do not address the case of singers, further research will identify which binaural monitoring solution would best support professional singers' performance needs. Future research will also include tests with more musicians of different popular music genres to find solutions in terms of beat spatialization, which we know can be tricky in binaural, especially for hip hop [47].

To circumvent the hesitation to acknowledge the impact of monitoring technology on professional performers' musicality among practitioners, we encourage researchers to adopt a post-performance procedure, for instance through the analysis of performers' take choices a few weeks after the recording session to analyze the potential interconnection between the experimental condition and the best musical result [62]. This approach calls for conducting case studies that are fully integrated into real-life recording sessions that last several days. Also, future studies should further examine music performers' perception of *acoustic realism* when creating music in real-life situations with binaural monitoring, and how this perception depends on the cultural context (musical genre, ensemble's habits) and the acoustic situation (acoustic separation or not, size of the venue, amplified instruments or not). To that end, it would be

interesting to compare three recording setups, such as instrumentalists being in the same room without headphone monitoring, instrumentalists being in the same room with binaural monitoring to augment their natural hearing, and instrumentalists being in separate rooms and hearing each other through binaural monitoring. This investigation could also help to refine the potential of AAR and AMR approaches from a practical point of view, and thus inform the design of future headphone monitoring systems. Furthermore, and with respect to the emerging concept of acoustic realism, a large longitudinal study should be conducted to identify the duration requirements of a training procedure with non-individualized HRTFs to reach an optimal level of performers' ability to externalize binaural audio cues, as well as to appreciate the intelligibility and comfort of a binaural mix. In that respect, using complex musical stimuli during the training procedure is advised, instead of non-ecological stimuli such as pink noise. At last, only few binaural music productions have been released on the market so far, and we hope that our research will inspire more sound engineers to explore binaural mixing techniques, and the music industry to give a chance to this 3D audio format.
