Simulation and auralization of room acoustics

Binaural recording with ANC headphones in the anechoic chamber
© Fraunhofer IBP, Benjamin Müller
Binaural recording with ANC headphones in the anechoic chamber

We make innovative room acoustics visible and audible

Simulating room acoustics is not only an effective tool when it comes to planning acoustics but also for research purposes. Analytical models are used to estimate reverberation times according to Sabine or Eyring. With simulation and auralization, we can extend the possibilities of such models to rooms such as open-plan offices, in which the prerequisites of a diffuse sound field and an even absorption of sound are not fulfilled.

The computer-aided simulation of room acoustics provides a multitude of acoustic parameters that go far beyond the calculation of reverberation times - such as the calculation of speech intelligibility (STI), the reduction in sound level on doubling the distance or the distribution of sound levels. Based on this, we also create an auralization of the room, i.e. we make the room acoustics audible at various points in the modeled room. In this way, the room can be “listened to”, which is often extremely useful when evaluating simulation results. Even people unfamiliar with acoustic parameters can get an idea of the “sound” of a room before it is built.

Simulating room acoustics is also important for research purposes. For example, we can assess how the acoustics or speech intelligibility of historical buildings or places such as the Curia Iulia or the Forum Romanum used to be, even if they ceased to exist a long time ago. This allows us to investigate how many listeners could be reached during a speech and how quickly Julius Cesar probably spoke at that time.

To simulate room acoustics, we use current commercial software (Odeon). However, the quality of the results depends more on the model generated and the input data. Our experts have decades of experience in simulating room acoustics. Despite this, the models are usually compared with measurements and validated.

To create auralizations, we use impulse responses and our own source signals, which are recorded under optimal conditions in our anechoic chamber. This enables us to create high-quality auralizations that take into account the particularities of different sound sources.

We simulate room acoustics as part of our research work on rooms with special functions, such as open-plan offices, restaurants, swimming pools, sports halls and classrooms, as well as on the acoustics of historical monuments. We cooperate closely with colleagues from the fields of cognitive ergonomics and psychoacoustics. Our aim is to develop room acoustics parameters that correlate well with the subjective perception of users. Because we study room acoustics for the people who use the rooms.