Sebastian J. Schlecht
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pyFDN is an open-source Python library for designing, simulating, and analyzing feedback delay networks (FDNs). It provides reusable tools for common FDN workflows, including feedback-matrix generation, loop-filter design, pole analysis, and echo-density evaluation, with support for differentiable audio processing through FLAMO . Documentation · Source code · PyPI package
I am excited to join Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany. On April 2024, I will start a new group in the Chair of Multimedia Communications and Signal Processing. A short interview was published at the university blog .
Download BibTeX Will J. Cassidy , Gian Marco De Bortoli , Karolina Prawda , Philip Coleman , Russell Mason , Tapio Lokki , Sebastian J. Schlecht , Enzo De Sena , "Active Acoustic Enhancement Systems: A Review," The Journal of the Acoustical Society of America , vol. 159, no. 4, pp. 3533--3557, 2026. DOI Code BibTeX Kyung Yun Lee , Nils Meyer-Kahlen , Karolina Prawda , Vesa Välimäki , Sebastian J.…
Comparing different listening positions in a room The BRIRs are composed of two measurement positions as seen in the figure. The BRIRs on this website are the measurements in magenta: S2→R5 and S2→R2. Figure 1: Illustration of the source (S) and receiver (R) positions used to make up the listening test conditions. Microphones and loudspeakers were oriented facing north and south, respectively,…
We are hiring a Master thesis worker for the science-art project ‘R,’ which revolves around co-evolution between humans, animals, and technical agents. The acoustic niche hypothesis states that all agents in a shared acoustic ecology evolve to divide the sonic spectrum to allow effective intra-species communication. The project aims to create multiple artificial life forms that learn to…
Sebastian J. Schlecht, Monday, 31. October 2022 Test learning a clipping function with MLP import torch import torch.nn as nn import torch.nn.functional as F import torch.optim as optim import numpy as np import matplotlib.pyplot as plt # define Dataset class Dataset ( torch . utils . data . Dataset ): def __init__ ( self , num , clip ): self . input = torch . randn ( num , 1 ) self . labels =…
The application period for Master’s studies in Acoustics and Audio Technology is in December. The Acoustics and Audio Technology major is part of the CCIS Master’s program at Aalto.
A team of four Aalto University students — Pietari Nurmi, Kamila Kondraciuk, Mia Savo and Teodors Kerimovs — won the gold medal in Category 2: Audio Drama / Documentary / Soundscapes at the 6th European Students 3D audio competition. The winning project was the Spatial Audio Book (fairy tale) “Hansel and Gretel” which could be called a proof of concept for spatially mixed audiobooks.…
Inside the Quartet is a study of musical intimacy and communication. It, therefore, translates naturally to virtual reality with a brand new way of expression. The virtual scenery, both visually and sonically, is captured with precise technology to bring the spectator directly into the musical circle. For this, the capture combines 360 video and audio live recordings with acoustic and photographic…
Rapolas Daugintis (MSc AAT), Michael McCrea (MSc AAT), and Selina Oakes (MA ViCCA, School of Art), together received the Bronze Award at Europe’s Fifth Student 3D Audio Production Competition , in the category of Contemporary / Computer music, for their spatial sound composition The edge of the sea chatters with a lifetime of echoes, whistles and blows . The piece was streamed live from IEM…
Adobe Medium Gravity Sketch
Adobe Medium Gravity Sketch
Adobe Medium Gravity Sketch
Introduction The Aalto Virtual Planetarium is a tour of the inner Solar System, with the grand structures of planetary magnetospheres show through the eyes of a space physicist. Aimed at education and outreach, the immersive virtual reality experience demonstrates Aalto space research, including the plasma physics of the Sun, magnetosphere of inner planets, the Finland100 satellite and cometary…
Panorama of silo with measurement setup. Photo: Andrea Mancianti Sound artist and Doctoral student at Aalto University Andrea Mancianti recorded a peculiar acoustic environment at the outskirts of Helsinki, Finland - the Silo 468. Due to its highly reflective, circular walls, the sound reflections strongly depend on where the sound source is and where you as a listener stand. Previously, the music…
Feedback delay networks (FDNs) are recursive filters, which are widely used for artificial reverberation and decorrelation. While there exists a vast literature on a wide variety of reverb topologies, this work aims to provide a unifying framework to design and analyze delay-based reverberators. To this end, we present the Feedback Delay Network Toolbox (FDNTB), a collection of the MATLAB…
Overview Required Hardware Parts of this course can be completed without a headset. However, for the full experience of these tutorials, you require an HMD. Although, recent VR frameworks allow more cross-platform development, it is highly recommended to use an Oculus Quest device. It is possible to complete this course with a windows or a mac. However, windows machine have in general much better…
Overview Required Hardware Parts of this course can be completed without a headset. However, for the full experience of these tutorials, you require an HMD. Although, recent VR frameworks allow more cross-platform development, it is highly recommended to use an Oculus Quest device. It is possible to complete this course with a windows or a mac. However, windows machine have in general much better…
Setup Quest First, perform a Factory Reset of the Oculus Quest. Create an Oculus Developer Account . It seems that it is still possible to NOT connect to a Facebook account and also not require a credit card. What you want is called an unmerged account. Setup Oculus Quest with the Oculus mobile app . Then Enable Developer Mode . It seems that it is easiest if you create a new organization. Setup…
Setup Quest Create a Meta Quest Developer Account . This only requires an email address and a phone number for 2 Factor Authentication. You do not need it to be connected to any Facebook account or credit card. Install the Meta Quest (Oculus) mobile app on your phone and sign in with your Meta account. We provide you with Quests that are already in the factory reset state, which need to be setup…
Setup Quest Create a Meta Quest Developer Account . This only requires an email address and a phone number for 2 Factor Authentication. You do not need it to be connected to any Facebook account or credit card. Install the Meta Quest (Oculus) mobile app on your phone and sign in with your Meta account. We provide you with Quests that are already in the factory reset state, which need to be setup…
Setup Unity Find here the System Requirements . First, let’s Install Unity . In particular: Install Unity Hub Install 2019.4.40 or higher (LTS) Install Android SDKs Get Started with Unity Every programming language has idiosyncracies, depending on your previous background, some structures are intuitive and some others are confusing. Unity has a well-maintainted manual; make it your habit to…
Setup Unity Find here the System Requirements . First, let’s Install Unity . In particular: Install Unity Hub Install 2022.3.8 (LTS) Install Android SDKs Get Started with Unity Every programming language has idiosyncracies, depending on your previous background, some structures are intuitive and some others are confusing. Unity has a well-maintainted manual; make it your habit to read it. It…
Data plots are at the heart of many technical papers. These are the first things readers look at, and sometimes they are the only thing they remember. Therefore, good articles need consistent, sharp, and expressive visualizations. In my opinion, the best way to create such a plot from Matlab is Matlab2TikZ . matlab2tikz is a MATLAB script to convert native MATLAB figures to TikZ/Pgfplots figures…
This page is a collection of techniques and tools I use to enhance my academic workflow. This guide is mainly intended for MSc and Ph.D. students looking for a streamlined research process. Naturally, tools change rapidly, and many recommendations are little more than promoting my taste. Nonetheless, these are my practices that have endured for the better or worse for multiple years. Further,…
We often rely on our audition when evaluating object motion, like, for example, the velocity of an approaching car. Can acoustic cues provide us with information about our motion, real or illusory? While visually-induced illusory self-motion (termed vection) has been extensively studied over more than a century, research on auditory vection cues has received only minor attention. This project aims…
Avatars are a central component of the virtual reality experience. In this project, we explore avatars’ spatial capturing visually and sonically and integrate them into a VR environment. The visual volumetric capturing uses the new Azure Kinect depth-sensing cameras and Depthkit . Post-processing of the capture is performed in Sense XR Studio . Audio is recorded in the anechoic chambers of…
Hide and Seek is an audio-based VR game strongly inspired by the minigames of Half+Half . The project is meant to be a technical proof-of-concept establishing a Unity VR multiplayer game with voice and sound communication. The multiplayer infrastructure is handled by Normcore , and the target platform is Oculus Quest. The game should include basic gameplay, hand gesture tracking, locomotion, and…
Graphical abstract
The corresponding Oculus Quest app can be downloaded from https://space.aalto.fi/software/ . Immersive Sonic Journey Your browser does not support this video format. Audio only version Your browser does not support the audio element.
Your browser does not support this video format. --> Listening Test Below are the listening test samples used in the perceptual evaluation of the reverberation signals. For more details on the generation, please see the accompanying paper. Test 1 Test 2 Test 3 Test 4 Credits Trackswitch.js was developed by Nils Werner, Stefan Balke, Fabian-Rober Stöter, Meinard Müller and Bernd Edler.
Goal Create photogrammetric scans of AcousticsLab facilities (10-15 rooms) in Otaniemi, Espoo. Work packages Make scans of the rooms with iPad Clean up scans with 3D modeling software, e.g., Blender Create VR-ready version: smoothing, decimation, re-texturing Hardware iPad Pro 2020 with LIDAR scanner Requirements Good command of an appropriate 3D modeling software Interest/skills in photogrammetry…
--> remote/displaced allows for an immersive exploration of a virtualized physical space: Öljysäiliö 468, a vast, decommissioned and repurposed oil tank in East Helsinki. Due to its shape and materials, its acoustics are extremely peculiar, with long reverberation times, shimmering echoes and immersive radiating patterns. In addition, it is an almost magical site for a modern sonic ritual due to…
A String is not a Point Source In this first animation, we present the spatio-temporal behavior of a string. Obviously, each point of the string oscillates in a different way: Your browser does not support this video format. In the next step, we show how a point source model of a string would excite a room. To this end, the string is picked up only at a certain position (dashed line) and emitted…
Introduction Light Train is a small scale experiment to learn and explore various features for Unity3D, XR Interaction Toolkit, and Oculus Quest. The scene is illuminated by a little train equipped with a spotlight. The objects in the set were created with Tiltbrush and imported via Poly Tookit for Unity . The music was composed with some foley recordings and a few piano and synth tracks in…
--> Out of body is a contemplative study on self-perception. Before visitors enter the virtual world, a full-body scan in a lying position is prepared and integrated into two imaginary landscapes. The inanimate body, an abstracted picture of self, is then visited by the experiencer. On the contrary, the sensation of the own physical body is occluded by the VR displays and transforms the self into…
The same Ambisonics music can sound very different under different acoustic conditions. Specifically, it has been observed that many pieces sound better in slightly more reverberant rooms than in completely dry reproduction. This work aims to assess Ambisonics playback in different rooms, also using the variable acoustics chamber at the Aalto Acoustics Lab. Prior work has been done with simulated…
Reverberation in rooms is often thought to evolve towards Gaussian noise gradually. This transition from distinct early reflection to dense late reverberation is a critical metric for characterizing the sound of a room. Various ad-hoc measures have been proposed to quantify these transitions. This work aims to use classic statistical normality tests and energy compensation techniques to evaluate…
Musical Dissonance The question when musical tones sound in (dis/con)sonance, i.e., in a (un)pleasant accordance, is age-old and reaches back in time to the Ancient Greeks. In modern psychoacoustics, as pioneered by Hermann von Helmholtz, the dissonance is explained through the sensory stimulus of multiple, simultaneously presented simple oscillations, i.e., sinusoids or pure tones. The hypothesis…
Writing a technical paper or thesis can be hard. But, it shouldn’t be harder than it needs to. The typesetting system LaTex has become the de-facto standard for writing technical content, especially for those manuscripts which require an army of mathematical notation, variables, and operators. Here, I like to offer another helpful trick to make your writing more consistent by using macros .…
Over fifty years, researchers around the globe have developed countless artificial reverberators and among them prominently the Feedback Delay Network (FDN) and its many cousins. Although explicit system architectures are rarely published, nonetheless, there exists a set of notable examples. In this work, we collect, implement, and analyze delay feedback structures from the vast literature in a…
The aim of Mixed Reality (MR) technology is to overlay the physical reality with virtual stimuli indistinguishable from real stimuli. In the visual domains, the main technical paradigms of MR are see-through cameras or transparent glasses. Analogously, in the auditory domain, the two competing models are hear-through and transparent headphones. In this work, we evaluate the fidelity and…
Feedback Delay Networks (FDNs) are one of the most efficient methods to synthesize artificial reverberation. Although high-order FDNs can achieve high-quality results, they also tend to be too dense and have increased computational complexity. On the contrary, low-order FDNs exhibit (if not carefully tuned) metallic and unpleasant resonances. This work aims to investigate the mathematical…
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Your browser does not support this video format. Presentation at 23rd International Conference on Digital Audio Effects (DAFx2020)
