MusicLab Copenhagen was a unique research concert featuring the world-renowned Danish String Quartet in a naturalistic setting. The audience was split between one group physically located in the hall, another group listening to a radio broadcast, and a third group watching a live stream. Qualitative and quantitative data were captured from both musicians and audiences, resulting in a comprehensive dataset that can be used to address many research questions. This document introduces the dataset, explains its structure, and reflects on the related data collection, storing, publishing, and archiving processes.