Navigate through acoustic environments with six degrees of freedom.

Concept

Real spaces are not isolated boxes — rooms connect through doorways, corridors, and open plans, and listeners move freely through them. Reproducing this experience in virtual and augmented reality requires rendering spatial audio that evolves naturally as the listener walks, turns, and transitions between coupled acoustic environments.

Our research tackles the full pipeline: from measuring and modeling the acoustics of connected spaces, to rendering smooth room transitions, to evaluating whether the result sounds convincing to listeners.

Room Transitions in Coupled Spaces

When sound travels between connected rooms, energy initially increases before decaying — creating a convex energy decay curve rather than the typical concave shape. We characterized this fade-in phenomenon[1][2] and developed auralization methods[3][4] for smooth transitions between coupled acoustic environments, including real-time rendering[5].

Code: fade-in-reverb — implementation of fade-in reverberation for multi-room environments using the common-slope model.

Demo: Fade-in reverb examples — audio demonstrations of room transitions.

Data: Room transition datasets — measured acoustic data of transitions between coupled rooms.

Common-Slope Late Reverberation Model

The common-slope model[6] decomposes late reverberation into shared decay slopes with direction-dependent amplitudes, enabling efficient, physically motivated rendering of complex reverb fields. Its extension to coupled rooms[7] and acoustic radiance transfer[5] provides a complete framework for spatial rendering in multi-room environments.

Code: CommonSlopeAnalysis — MATLAB toolkit for common-slope analysis of late reverberation.

Demo: Common-slope listening examples — interactive demonstrations of the model.

Demo: Dynamic rendering — real-time common-slope rendering for games and VR[8].

Spatial Room Impulse Response Rendering

Reproducing measured spatial room impulse responses (SRIRs) with full 6DoF listener movement requires interpolation between sparse measurement positions and anisotropic multi-slope resynthesis[9]. We developed methods for resynthesizing SRIR tails that preserve directional decay characteristics lost in conventional processing.

Code: Directional Multi-Slope RIR Resynthesis — anisotropic multi-slope decay envelope resynthesis.

Demo: Resynthesis listening examples — audio comparisons.

Code: SRIR Interpolation Toolkit — perceptually informed interpolation of SRIRs between measurement positions.

Autonomous Room Measurement

The ARTSRAM robot twin system[10] uses autonomous Roomba-based platforms with loudspeakers and microphone arrays to collect hundreds of room impulse response measurements through random walk procedures — no prior grid planning required.

Demo: ARTSRAM project page — measurement setup and results.

Velvet Noise for Spatial Reverberation

Sparse pulse sequences (velvet noise)[11] provide an efficient basis for multichannel reverberation rendering. Dark velvet noise extends this to non-exponential decay modeling, and our perceptual studies establish quality thresholds for when rendering artifacts become audible.

Demo: Multichannel velvet noise rendering — multichannel interleaved velvet noise.

Demo: Velvet-noise FDN — spatial reverberation with velvet noise.

References

1. Thomas McKenzie, Sebastian J Schlecht & Ville Pulkki (2021). Acoustic Analysis and Dataset of Transitions between Coupled Rooms. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).
2. Thomas McKenzie, Sebastian J. Schlecht & Ville Pulkki (2021). Auralisation of the Transition between Coupled Rooms. International Conference on Immersive and 3D Audio (I3DA).
3. Thomas McKenzie, Nils Meyer-Kahlen, Christoph Hold et al. (2023). Auralization of Measured Room Transitions in Virtual Reality. Journal of the Audio Engineering Society.
4. Georg Götz, Teodors Kerimovs, Sebastian J. Schlecht et al. (2024). Dynamic Late Reverberation Rendering Using the Common-Slope Model. 6th AES International Conference on Audio for Games.
5. Matteo Scerbo, Sebastian J. Schlecht, Randall Ali et al. (2024). A Common-Slopes Late Reverberation Model Based on Acoustic Radiance Transfer. Proceedings of the 27-Th Int. Conf. on Digital Audio Effects (Dafx24).
6. Georg Götz, Sebastian J. Schlecht & Ville Pulkki (2023). Common-Slope Modeling of Late Reverberation. IEEE/ACM Transactions on Audio, Speech and Language Processing.
7. Georg Götz, Sebastian J. Schlecht & Ville Pulkki (2022). Common-Slope Modeling of Late Reverberation in Coupled Rooms. Proceedings of the 24th International Congress on Acoustics (ICA).
8. Kyung Yun Lee, Nils Meyer-Kahlen, Georg Götz et al. (2024). Fade-in Reverberation in Multi-Room Environments Using the Common-Slope Model. AES 5th International Conference on Audio for Virtual and Augmented Reality (AVAR).
9. Christoph Hold, Thomas Mckenzie, Georg Götz et al. (2022). Resynthesis of Spatial Room Impulse Response Tails with Anisotropic Multi-Slope Decays. Journal of the Audio Engineering Society.
10. Georg Götz, Sebastian J. Schlecht, Abraham Martinez Ornelas et al. (2021). Autonomous Robot Twin System for Room Acoustic Measurements. J. Audio Eng. Soc.
11. Nils Meyer-Kahlen, Sebastian J. Schlecht & Vesa Välimäki (2022). Colours of Velvet Noise. Electronics Letters.