New research aims to develop a method for real-time reproduction of acoustics when moving around in a digital model of a coming building while wearing VR glasses and headphones.
Building processes are becoming increasingly digital. This also applies to the initial phase, where virtual models make it possible to move from room to room and get a visual impression of a building while it is still on the drawing board.
However, the acoustics of a future building are most often provided in the form of a series of numerical values that do not allow for a similar sensory experience of what the acoustics will be like in the different rooms of the building.
The current methods for calculating and reproducing the acoustics of a room are based on simulations of sound waves and on geometric acoustic models. The latter is the most widely used method, but it lacks precision in reproducing acoustics from particularly small rooms and at low frequencies (the deep tones). Models based on sound waves can provide a precise and realistic representation of sound, but, in turn, require calculations that it may take a couple of days to complete for a whole room.
Precise reproduction necessary
A research project between DTU, Rambøll, and Ecophon will develop new methods and strategies for creating real-time reproduction of room acoustics that is as close to reality as possible. This is done on the basis of theoretical advanced mathematics, new technologies, and scientifically based computer calculations.
“The goal is to find a compromise between the desired high precision and the time it takes to calculate the acoustics. One of the things that I’m looking at is the use of a mathematical method—the reduced basis method—to reduce the time for computer calculations. The method is used in many other areas, but it hasn’t yet been applied in the field of acoustics,” says Hermes Sampedro Llopis, DTU Electrical Engineering, who is responsible for the development.
“During the process, my focus is on the accuracy of the results. In an architectural model, it’s essential that the acoustics are reproduced completely correctly and very close to reality, regardless of whether you’re standing in the middle of the room or at one of the walls,” says Hermes Sampedro Llopis.
If we succeed in developing new methods for acoustic reproduction, this will be of importance to—for example—architects’ initial work on designing a building. Here, the current methods cannot be used, as the architect needs quick calculations of what a change in materials or the geometry of the room means to the acoustics.
The coming clients and owners are also very interested.
“Our customers are pleased with the visual experience they get today by moving through a model of a coming building while wearing VR glasses. We also want to be right at the forefront and exploit the opportunities that digitalization offers for linking the acoustics to this experience,” says Jesper Bo Andersen, Senior Consultant in Acoustics and Noise in Rambøll.
“However, the development of a new method for real-time reproduction of acoustics is not a conventional development task that we can perform ourselves. This is mathematically based research, on which we’re pleased to collaborate with researchers from EPFL, DTU Compute and DTU Electrical Engineering,” says Jesper Bo Andersen.
Acoustics affect learning and efficiency
Another participant in the research project is Ecophon, which manufactures sound-absorbing material for use in—for example—walls and ceilings.
“We work with acoustic solutions that are especially used in schools, hospitals, and workplaces where acoustics are of great importance to learning and efficiency. It’s therefore important for us to develop a method that can give the acoustics an educational aspect and make it clear to our customers what different solutions mean to the acoustics of—for example—a canteen or an entrance,” says Acoustics Specialist Erling Nilsson, Ecophon.
Hermes Sampedro Llopis’ research will stretch over the next couple of years. In addition to working with the development of new methods and utilization of modern technologies for demanding calculations and the creation of opportunities in VR, he will also conduct a number of tests in DTU’s advanced sound laboratories. This is done to verify that the acoustic experience is correct and perceived uniformly, regardless of who moves through an architectural model wearing headphones and VR glasses.