Visualizations have long been established in construction, allowing designs to be experienced as images or 3D models before the first shovel breaks ground. But what about acoustics? This is where auralization comes into play. For our sense of hearing, auralization does what visualization does for our sight: it makes architecture acoustically perceptible. Auralization can provide early insights into the acoustic quality of a space—such as a concert hall—during the planning phase. Experiencing this with one’s own hearing allows for a deeper understanding and is a valuable complement to assessing expected sound characteristics.
Does the acoustics suit the intended use? Is the sound in the front row as immersive as expected, and what does it sound like from the last row of the balcony? Auralizations help answer pressing questions and support key planning decisions by predicting how a space will sound, considering parameters such as room geometry, materials used, and sound source locations. Differences, advantages, and disadvantages of various design options and planning variations become clear and are easier to compare.
Existing simulation software for creating auralizations is mainly a planning tool for acousticians. To make it more accessible for a broader audience, Kai Heller (planning engineer at Müller-BBM Building Solutions) developed the Auralization Explorer during his master’s studies at TU Berlin—a user-friendly and immersive platform that enables interactive exploration of a space’s acoustics. Müller-BBM Building Solutions has since advanced the Auralization Explorer concept for practical application, making it possible to experience room acoustics interactively. Each use is precisely tailored to the specific acoustic requirements of the project, whether to demonstrate how a concert hall sounds from different seating areas or to illustrate the soundscape of foyers without acoustic measures.
The system features a large touchscreen displaying the room (for example, a concert hall) from a bird’s-eye view. With a tap, users can select their listening position: first row or perhaps second-tier side box? With integrated head-tracking in the headphones, precise spatial localization of sound is possible. Turning one’s head, the acoustic scene remains stable, with the orchestra seemingly playing directly in front. A second large screen shows the selected listening positions from a first-person perspective, enhancing the illusion of sitting right in the concert hall.
The interactive experience is implemented using the Unity game engine, increasingly used in architecture and engineering. The user interface works in combination with a room acoustic simulation software, based on ray tracing, which traces the path of sound waves from a source, such as a cello, accounting for reflection and diffraction effects through the space until it reaches the listener’s ear. This simulation captures the acoustic factors in a simplified model, providing an approachable experience of the complex interaction between sound and space, making it perceptible for the human ear and more aligned with reality.
The Auralization Explorer also opens up new possibilities for presenting and communicating room acoustic concepts. In stakeholder presentations, public participation, or project exhibitions, it serves as a valuable tool to make acoustic planning tangible. Through the listening experience, all parties gain a better understanding of the planned acoustics, allowing them to make well-informed decisions. Particularly in architecture and construction planning, where visual representation predominates, the Explorer addresses the challenge of illustrating acoustic dimensions. With the Auralization Explorer, architects, clients, and acousticians can work closely together and discover the best acoustic solutions.
Additionally, the Explorer is an effective tool for public outreach. In exhibitions or public events, complex concepts in room acoustics are communicated in an engaging way, allowing visitors to not only see but also hear the current state of planning. Thanks to the modular design of the game engine, additional information, such as interactive details about the construction project or audiovisual content, can be incorporated into the experience.
The Auralization Explorer was developed as part of Kai Heller’s master’s thesis in the Audio Communication Department at TU Berlin and subsequently implemented at Müller-BBM Building Solutions as part of acoustic services. Since 2023, Kai Heller has been working as a planning engineer in audiovisual systems at Müller-BBM Building Solutions.
