Psychoacoustics Research: Advancing the Understanding of Human Auditory Experience
The field of psychoacoustics is dedicated to understanding how humans perceive sound, bridging the gap between the physics of acoustics and the subjective experience of hearing. Recent developments in this area are pushing the boundaries of audio technology and sound design, with a focus on creating more immersive and realistic auditory experiences. This article highlights some of the latest research and advancements in psychoacoustics, exploring how these findings are being applied in various fields.
Psychoacoustic Masking
Applied Psychoacoustics Lab at the University of Huddersfield
The Applied Psychoacoustics Lab (APL) at the UK’s University of Huddersfield serves as an experimental hub created to advance our knowledge of the mechanism of human auditory experience. It provides perceptually-motivated solutions to audio engineering problems. Founder/Director of the APL, Prof Hyunkook Lee, explains, “Recently we’ve been focusing on virtual acoustics for extended reality applications.”
The APL is deeply involved in studying the interaction between audio and visual cues using VR headsets and display systems. He continues, “We’re also conducting lots of experiments using VR headsets and also display systems to look into the interaction between audio cues and visual cues. That’s highly relevant for creating immersive experiences. It’s not just audio that gives you an immersive audio experience - because we see things in real life.
Upgrading the Listening Environment
For the last decade, 24 Genelec 8040 monitors combined with a pair of 7070 subwoofers have been used to reproduce audio in APL’s critical listening room.
Lee recalls, discussing the decision for the upgrade, “There were two reasons basically. The Ones provide excellent tonal consistency wherever you sit in the room, which is very important when you have a lot of people in this space. When we hosted a recent AES International Conference on Spatial and Immersive Audio, we had 21 people in this room. And wherever they sat, they had an excellent experience.
He continues, “The second reason was for our research. We needed coaxial monitors because when you do localisation tests, the acoustic centre position is always important. With the 8040s, you have to take the average between the tweeter and woofer.
The new setup allows APL to create a Dolby Atmos 9.1.6 space, while the remaining 8040s ensure that this can be expanded to cover higher channel count formats such as NHK’s 22.2 standard. A further advantage that APL has found from upgrading is the simplicity of room switching made possible with GLM software.
“We can tune the whole room with the 9.1.6 system in less than five minutes and that was a big factor,” says Lee. “GLM makes a huge difference, especially with immersive audio. Of course, you get a very significant difference with stereo as well.
Genelec Monitors at APL
Future Research Directions
With the new system in place, APL is continuing its efforts to help improve our understanding of immersive audio environments.
“Recently, we’ve been focusing on binaural audio for virtual monitoring and extended reality applications,” explains Lee. “And my current research focuses on what kind of roles audio plays in providing an immersive experience. And for that, it’s all about understanding what content producers really think about immersive audio, and what kind of experience users expect from these immersive systems. We need to understand each other and try to narrow the gap and work together in a collaborative environment.
RISD’s Studio for Research in Sound and Technology (SRST)
RISD’s Studio for Research in Sound and Technology (SRST, formerly known as the Spatial Audio Studio) serves as an interdisciplinary hub for sound design experimentation as well as research in sonic interaction, experience, composition and performance. Headed up by Professor Shawn Greenlee 96 PR, the studio is located on the mezzanine level of 15 West.
Johnson: What’s really unique about the space is that you can conduct research in conjunction with materials, inside a framework for actually hearing and experimenting with sound. That radically alters how your research might unfold. Being in a space where sound is created in such an intentional way reframes the conversation and reorients the community.
Shonuga-Fleming: Even listening to existing music in that super-quiet space allows you to hear all the details in ways you never could before. And sound design is much more intuitive when you can hear everything.
Cetilia: In my Sound Synthesis and Sonic Practices classes offered through the Digital + Media department and Computation, Technology and Culture concentration, I try to offer opportunities for collaboration.
Greenlee: And it’s an entirely interdisciplinary space, which means it’s a great place for RISD students and faculty to connect with people in other departments.
Interdisciplinary Approach to Sonic Research
Johnson: I think that part of it is trying to conceive of sound as an invisible material and to understand how it relates to the larger, nebulous world of aesthetics.
Greenlee: Absolutely, yes. Students are already working with sound, for example in the Film/Animation/Video department, but it’s also becoming more and more prevalent in other departments, like Painting and Sculpture, in which students are creating immersive installations and performances that incorporate audio components. Think about all of the headphones and loudspeakers you’re likely to encounter in a gallery exhibition. Sound design is also a key factor in many fields, including industrial design and graphic design, when multi-sensory experience is fully considered.
“Sound is becoming more and more prevalent in departments like Painting and Sculpture, in which students are creating immersive installations and performances that incorporate audio components.”
Demps: I teach Spatial Dynamics classes in the Experimental and Foundation Studies division, so I’m working with undergraduate students who haven’t selected a major yet. One assignment I’ve been giving students is to build an archive of their favorite places and pay close attention to the places’ sounds as a way to understand and navigate space.
Shonuga-Fleming: I’m studying Architecture, and part of what we’re learning is how to design acoustically. I also took Shawn’s Spatial Audio class, which really opened me up to thinking about acoustic space architecturally: how sound is positioned in space, what the acoustics of the room contribute, etc.
Research on Difference Tones
Chechile: My research revolves around “difference tones,” which are sounds the ear generates in response to specific acoustic tone combinations. Difference tones are perceived as localized within the head, so they create an additional nested layer of spatial depth within the multichannel loudspeaker dome.
To work creatively with these tones, I conduct empirical research in psychoacoustics, and the results can be used in medical fields and in the hearing sciences but also in instrument design and applied sonic arts. At RISD, I’m expanding my Ear Tone Toolbox software and writing new creative works that employ the phenomenon, among other projects.
Difference Tones
Public Engagement and Collaboration
Demps: It was amazing: very informative but also grounded and down to Earth. It’s awesome to hear about how other folks are working, the problems they’re dealing with and how they’ve solved them. I always find inspiration in that.
Johnson: I’ve been following Camille Norment’s work for forever. It’s really philosophical.
Greenlee: And it’s important to note that the event-an insightful discussion facilitated by Alex and Assistant Professor Jess Myers-was co-sponsored by the Architecture department and the Fleet Library, so it really brought the RISD community together.
Greenlee: RISD’s Studio for Research in Sound and Technology is becoming a hub for new software, tools and ideas in the fields of sonic arts and sound design. It has been so exciting to see how the students leapfrog off one another’s research ideas.
Key Areas of Psychoacoustics Research
- Auditory scene analysis and sound object recognition: Research investigating how listeners distinguish between sound sources, process complex acoustic environments, and identify sound objects within natural and artificial soundscapes.
- Hearing loss, auditory perception, and assistive technologies: Studies examining how hearing loss alters psychoacoustic and cognitive aspects of sound perception, including changes in pitch, loudness, temporal and spatial processing.
This collection aims to bridge theory with application by highlighting work that spans from the core science of psychoacoustics to innovative implementations in real-world audio systems and soundscapes. We also welcome contributions that do not restrict to natural sciences, but that work in close relationship with, or make use of methods borrowed from the humanities and social sciences, e.g.