Percussion is one of the toughest tests for arena acoustics. Sharp attacks show up late reflections and echoes, and strong low-frequency energy builds up in large volumes, so rhythm can turn muddy for the audience. In this portfolio video, ALTA Integra presents drum sound acoustic modeling and auralization for the Gelora Bung Karno (GBK) Indoor Multipurpose Stadium in Jakarta, now known as Indonesia Arena. A 3D acoustic model predicts how the arena responds to live music, and auralization turns those results into audio that architects, owners and stakeholders can listen to before construction. Together with the speech auralization, it helped guide decisions on absorptive finishes, reverberation control and sound system design so the venue works for concerts as well as sports and ceremonies. It's for architects, acoustic and AV consultants, developers and venue operators working on large multipurpose spaces.