EASE and IMMI bridge sound design and noise assessment

A research collaboration between AFMG Technologies, Wölfel Engineering, TW Audio and Akustik Bureau Dresden has produced an Aggregate Point Source (APS) model designed to connect sound-system simulation with environmental noise assessment for open-air events.

The workflow, now integrated into EASE 5, addresses a longstanding difference between the way sound reinforcement systems and environmental noise are modelled. Sound system design typically accounts for the interaction and coherence of individual loudspeakers, while noise assessment models generally treat sources as incoherent and focus on factors such as directivity and environmental conditions.

The APS model creates substitute sound sources from detailed EASE 5 simulations. Groups of coherently operating sources are combined into Aggregate Point Sources that represent the far-field directivity of the underlying loudspeaker arrangement. These sources can then be transferred into IMMI, where they are used within the environmental noise forecast model. Data import and export between EASE 5 and IMMI are fully implemented.

The approach is intended to provide a more consistent workflow for analysing individual sound system configurations while accounting for their potential impact beyond the audience area. The research has been examined through a series of publications, including work presented at AES and DAGA, with reported practical forecast accuracy of approximately 1–3dB.

TW Audio was involved in the development through Tobias Goldmann of its development team, contributing measurements, simulation methods and practical sound system expertise. As part of the investigations, the manufacturer’s GLL models were revised and verified, with the resulting models achieving deviations of less than 1dB between measurement and simulation in the reported tests.

The workflow is available through EASE 5.81 and IMMI 2026, providing a route for acoustic consultants and system engineers to connect sound system design with environmental noise prediction for complex open-air events.