Unity App for Soundscape Design and Evaluation

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Ambient noise is an important aspect of landscape quality and has a significant impact on the health and well-being of humans and animals (Schulte-Fortkamp & Fiebig 2023, https://doi.org/10.1007/978-3-031-22779-0_1). When planning and designing landscape and urban development, noise protection is usually considered in relation to individual aspects such as traffic or wind turbines. However, the soundscape, i.e., the acoustic environment of a place as it can be perceived, experienced, and understood by people in a given context, consists of a superimposition of multiple sound events that interact with the physical landscape (Schulte-Fortkamp & Fiebig 2023, https://doi.org/10.1007/978-3-031-22779-0_1). Therefore, to design high-quality soundscapes, their perception must also be assessed.

Traditional simulations typically employ abstract models that focus on the acoustic quality of individual sounds rather than the interplay of multiple sounds. Furthermore, theory-based audiovisual perception of space and digital reconstruction of soundscapes are not widely promoted in education today (Brühne 2023, https://doi.org/10.1553/gw-unterricht171s72). Our main motivation was therefore to integrate visual and auditory 3D data, and, thus, combine two different 3D models, to enable students and others, who mainly use visual design tools and are not familiar with environmental acoustics, to work with the soundscape.

The aim of the project was to develop an app for auralizing virtual 3D landscape environments. The app was designed to illustrate theoretical principles of soundscape and make them tangible. Students should apply these principles to design outdoor spaces and evaluate changes in terms of their acoustic quality. In this way, students should develop skills in dealing with the quality of soundscapes, sharpen their spatial perception of specific effects such as the acoustics of open or closed landscape situations, and be motivated to incorporate the soundscape into early planning and design phases.

For this purpose, an app was developed that was implemented in the Unity game engine (Unity Technologies 2025, https://unity.com/products/unity-engine; Gutscher et al. 2025, https://doi.org/10.5281/zenodo.14770931, https://doi.org/10.3929/ethz-b-000733161). We developed a prototype of a mixing tool with Panoramix (IRCAM 2025) controlled via a Unity interface using Open Sound Control (OSC) messages. This mixing tool spatializes sounds from various sources, such as cars, trains, or birds, in different formats (mono, stereo, ambisonics files) into a coherent audio scene. In addition, a general acoustic ambience and occlusion effects from buildings can be simulated. With a “ScenarioChanger,” users can prepare different audiovisual scenes in Unity to support easy presentation of soundscape designs.

The developed app was implemented during the Innovedum-project in two courses at Master’s level with students in the fields of spatial development and infrastructure systems and of landscape architecture. The app was intentionally integrated into specific lessons of the courses to support students in achieving defined learning objectives. The general objectives were fostering awareness of soundscape principles, familiarizing students with the app to reproduce soundscapes, and enabling them to design, analyze and evaluate audiovisual landscape qualities.

In the course “Landscape Acoustics”, the app was used to foster the students’ understanding of the spatial stratification or layered structure of a soundscape, the interaction of sound sources such as masking effects, and it was tried to demonstrate room acoustics effects. In an exercise, the students experimented with sound source layering in a digital 3D environment. Then, the students placed recordings made in the real environment into the 3D model and analyzed the dominant frequency ranges. They identified sound types, categorized them into groups of sound sources, and assigned colors according to these eco-acoustic groups in the 3D model. Looking at the 3D model from above provided an analysis of the distribution of sounds per category. Further, students added new sounds and used the app to connect their spatial sound design with the 3D model to gain a better perception of scale.

In the course “GIS-based 3D Landscape Visualization”, a demonstration of the app was made with prepared scenarios. Both, the challenges of auralizing altered landscape situations and the functions of the app coming along with underlying principles of sound distribution and attenuation and their perceptual effects were presented. The students then applied the app in their own simulation trying to advance the perceived realism of their digital 3D environments and to communicate possible ambiences. These simulations were presented and discussed in class concerning their quality for intended planning tasks.

For evaluating the quality of the app as pedagogical medium in teaching and learning about soundscape, its design and evaluation, we combined different qualitative research methods to gain feedback from lecturers’ and students’ perspective. A “learning journal” was employed for the students to reflect on their learning progress. In addition, a questionnaire and a group discussion were conducted to collect feedback from students on the app’s effectiveness and usability and their perceived learning success. Observations and an interview with a lecturer revealed further strengths and weaknesses of the app and ideas for enhancement.

The app contributed significantly to students’ conceptual soundscape understanding. Lecturers and students noted that the interactive features of the app facilitated engagement with basic psychoacoustic concepts, such as spatial layering and masking effects of sounds. The students’ learning journals indicated a high level of comprehension of theoretical inputs. The app’s capacity to auralize sound in a dynamic 3D environment enabled students to connect abstract theoretical principles with tangible spatial representations, thereby reinforcing their understanding of sound as a critical component in landscape perception and planning.

Further, the app offered helpful possibilities, such as the ability to toggle sound sources, simulate spatial distribution, and explore acoustic scenarios using the “ScenarioChanger”. These functionalities motivated students to familiarize themselves with the app for reproducing environmental sound in a virtual audiovisual 3D model. However, some usability challenges caused difficulties. The Unity interface was described as unintuitive. Students encountered difficulties with basic operations, such as switching sound sources on and off, managing the audio library and navigation through the virtual 3D space.

Nevertheless, students engaged in exercises that involved placing real-world recordings into 3D models, analyzing dominant frequency ranges, and experimenting with spatial sound design. They stated that these activities provided them valuable insights into the perceptual effects of spatialized sound, such as distance of placed sounds and the perception of scale. But technical limitations of the app, such as limited number of tracks, issues with the audio library organization or constraints in duplicating game objects in the Unity game engine, still made design-oriented tasks difficult to implement. Students’ focus shifted on learning how to use the app instead of designing soundscapes by listening experiences.

Overall, the app proved to be a valuable teaching medium for enhancing theoretical understanding and offering motivating interactive learning experiences in soundscape design. Scenarios prepared with the app worked well to illustrate basic principles. To overcome the app’s weaknesses, technical advancement of the user interface is needed. In addition, a better documentation that is targeted to users who are not familiar with Unity and who use the app to primarily work with sound in a 3D setting is required. For implementing the app in other contexts and with further students, careful integration of the app into lectures is recommended to use its specific strengths in effective combination with other established teaching media such as soundwalks. For wide-ranging use, the prototype of the “Innovedum Soundscape Generator” is available on GitHub (https://github.com/danieborethz/Innovedum_Soundscape).