This article presents a detailed analysis of the acoustic design process of a soundproofed box intended for control room and mixing for immersive audio. The main objectives of the project were defined based on the quality criteria required for critical listening environments, particularly for Dolby Atmos rooms. The adopted methodological approach relies on predictive evaluations of key acoustic parameters, supported by studies and calculations conducted using advanced numerical models and software. Key phases of the design process include the optimisation of the box dimensions, the modal analysis for low-frequency response, the design of the listening layout and early reflections, the specification of the internal acoustic treatment. The technical solutions adopted aim to ensure an accessible and cost-effective environment, achieved through optimization in material and space selection while still meeting requirements.