@article{BrinkmannAspoeckAckermannetal.2021, author = {Brinkmann, Fabian and Asp{\"o}ck, Lukas and Ackermann, David and Opdam, Rob and Vorl{\"a}nder, Michael and Weinzierl, Stefan}, title = {A benchmark for room acoustical simulation. Concept and database}, series = {Applied Acoustics}, volume = {176}, journal = {Applied Acoustics}, publisher = {Elsevier}, issn = {0003-682X}, doi = {10.1016/j.apacoust.2020.107867}, year = {2021}, language = {en} } @misc{AckermannDomannBrinkmannetal.2022, author = {Ackermann, David and Domann, Julian and Brinkmann, Fabian and Arend, Johannes M. and Weinzierl, Stefan}, title = {Database: Recordings of a Loudspeaker Orchestra with Multi-Channel Microphone Arrays for the Evaluation of Spatial Audio Methods}, publisher = {TU Berlin}, address = {Berlin}, doi = {10.14279/depositonce-15774.3}, year = {2022}, abstract = {For a comparative physical and perceptual evaluation of conceptually different binaural rendering techniques, recordings are needed in which all other factors affecting the sound, such as the sound radiation of the sources, the room acoustic environment and the recording position are kept constant. To provide such a recording, the sound field of an 18-channel loudspeaker orchestra fed by anechoic recordings of a chamber orchestra was captured in two rooms with nine different receivers. In addition, impulse responses were recorded for each sound source and receiver. The anechoic audio signals, the full loudspeaker orchestra recordings and all measured impulse responses are available with open access in the SOFA 2.1 (AES69-2022) format.}, language = {en} } @misc{AspoeckBrinkmannAckermannetal.2019, author = {Asp{\"o}ck, Lukas and Brinkmann, Fabian and Ackermann, David and Weinzierl, Stefan and Vorl{\"a}nder, Michael}, title = {BRAS - A Benchmark for Room Acoustical Simulation}, publisher = {TU Berlin}, address = {Berlin}, doi = {10.14279/depositonce-6726.3}, year = {2019}, language = {en} } @article{AckermannDomannBrinkmannetal.2023, author = {Ackermann, David and Domann, J. and Brinkmann, Fabian and Arend, Jan M. and Schneider, Martin and P{\"o}rschmann, Christoph and Weinzierl, Stefan}, title = {Recordings of a Loudspeaker Orchestra with Multichannel Microphone Arrays for the Evaluation of Spatial Audio Methods}, series = {Journal of the Audio Engineering Society}, volume = {71}, journal = {Journal of the Audio Engineering Society}, number = {1/2}, publisher = {Audio Engineering Society}, doi = {10.17743/jaes.2022.0059}, pages = {62 -- 73}, year = {2023}, language = {en} } @article{AckermannFiedlerBrinkmannetal.2020, author = {Ackermann, David and Fiedler, Felicitas and Brinkmann, Fabian and Schneider, Martin and Weinzierl, Stefan}, title = {On the Acoustic Qualities of Dynamic Pseudo-Binaural Recordings}, series = {Journal of the Audio Engineering Society}, volume = {68}, journal = {Journal of the Audio Engineering Society}, number = {6}, publisher = {Audio-Engineering Society}, issn = {0004-7554}, doi = {10.17743/jaes.2020.0036}, pages = {418 -- 427}, year = {2020}, abstract = {The motion-tracked binaural (MTB) technique allows the dynamic, pseudobinaural rendering of spatial sound scenes recorded by a circular array of microphones on a rigid sphere. The system provides a multichannel live audio transmission from which a head-related signal with approximated interaural time and level differences can be derived and played via headphones, head tracking, and a corresponding rendering software. The latter is mainly calculating imperceptible interpolation between channel pairs during head movements. This contribution evaluates the potential of this format for the creation of virtual acoustic envi- ronments. Based on the technical realization of a 16-channel MTB array with omnidirectional diffuse field-corrected electret condenser microphone capsules, the plausibility of 8 and 16-channel recordings was tested against a physical sound source. Furthermore, the sound quality of the pseudobinaural rendering was assessed based on different items of the Spatial Audio Quality Inventory (SAQI) compared to a true dynamic binaural reference. The results show that the overall plausibility of the MTB signal with optimal interpolation is close to the reference. Even if there are small differences with respect to tone color and spatial sound source attributes, the degree of externalization and even the perceived source elevation were, despite the absence of pinna cues, well comparable to the true binaural reference.}, language = {en} } @article{BrinkmannAspoeckAckermannetal.2019, author = {Brinkmann, Fabian and Asp{\"o}ck, Lukas and Ackermann, David and Lepa, Steffen and Vorl{\"a}nder, Michael and Weinzierl, Stefan}, title = {A Round Robin on Room Acoustical Simulation and Auralization}, series = {Journal of the Acoustical Society of America}, volume = {145}, journal = {Journal of the Acoustical Society of America}, number = {4}, publisher = {Acoustical Society of America}, issn = {0001-4966}, doi = {10.1121/1.5096178}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-59034}, pages = {2746 -- 2760}, year = {2019}, abstract = {A round robin was conducted to evaluate the state of the art of room acoustic modeling software both in the physical and perceptual realms. The test was based on six acoustic scenes highlighting specific acoustic phenomena and for three complex, "real-world" spatial environments. The results demonstrate that most present simulation algorithms generate obvious model errors once the assumptions of geometrical acoustics are no longer met. As a consequence, they are neither able to provide a reliable pattern of early reflections nor do they provide a reliable prediction of room acoustic parameters outside a medium frequency range. In the perceptual domain, the algorithms under test could generate mostly plausible but not authentic auralizations, i.e., the difference between simulated and measured impulse responses of the same scene was always clearly audible. Most relevant for this perceptual difference are deviations in tone color and source position between measurement and simulation, which to a large extent can be traced back to the simplified use of random incidence absorption and scattering coefficients and shortcomings in the simulation of early reflections due to the missing or insufficient modeling of diffraction.}, language = {en} } @article{AckermannBrinkmannZotteretal.2021, author = {Ackermann, David and Brinkmann, Fabian and Zotter, Franz and Kob, Malte and Weinzierl, Stefan}, title = {Comparative Evaluation of Interpolation Methods for the Directivity of Musical Instruments}, series = {EURASIP Journal on Audio, Speech, and Music Processing}, volume = {2021}, journal = {EURASIP Journal on Audio, Speech, and Music Processing}, number = {1}, publisher = {Springer Nature}, issn = {1687-4722}, doi = {10.1186/s13636-021-00223-6}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-58992}, year = {2021}, abstract = {Measurements of the directivity of acoustic sound sources must be interpolated in almost all cases, either for spatial upsampling to higher resolution representations of the data, for spatial resampling to another sampling grid, or for use in simulations of sound propagation. The performance of different interpolation techniques applied to sparsely sampled directivity measurements depends on the sampling grid used but also on the radiation pattern of the sources themselves. Therefore, we evaluated three established approaches for interpolation from a low-resolution sampling grid using high-resolution measurements of a representative sample of musical instruments as a reference. The smallest global error on average occurs for thin plate pseudo-spline interpolation. For interpolation based on spherical harmonics (SH) decomposition, the SH order and the spatial sampling scheme applied have a strong and difficult to predict influence on the quality of the interpolation. The piece-wise linear, spherical triangular interpolation provides almost as good results as the first-order spline approach, albeit with on average 20 times higher computational effort. Therefore, for spatial interpolation of sparsely sampled directivity measurements of musical instruments, the thin plate pseudo-spline method applied to absolute-valued data is recommended and, if necessary, a subsequent modeling of the phase}, language = {en} } @article{AckermannBrinkmannWeinzierl2024, author = {Ackermann, David and Brinkmann, Fabian and Weinzierl, Stefan}, title = {Musical instruments as dynamic sound sources}, series = {Journal of the Acoustical Society of America}, volume = {155}, journal = {Journal of the Acoustical Society of America}, publisher = {Acoustical Society of America}, issn = {1520‑8524}, doi = {10.1121/10.0025463}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-58972}, pages = {2302 -- 2313}, year = {2024}, abstract = {Unlike electro-acoustic sound sources, musical instruments have a time-varying, dynamic directivity, due to the note-dependent radiation behavior of the instrument and due to the expressive movements that musicians perform with their instrument. While previous studies have generally examined the directivity of the static, unmoved instrument for specific notes played, we show the individual and combined contributions of these two factors to a temporal modulation of the radiation behavior, based on motion tracking of typical movement patterns for all instruments of a classical symphony orchestra and on the directivity measured for all partials over the entire pitch range of these instruments. The effect of this modulation, which is manifested by changes in timbre and room acoustic excitation, was determined by spectral variations in the free field and under reverberant conditions, as well as by a modulation of room acoustic parameters. Our results show that these effects are well above the just noticeable differences for all musical instruments and all perceptual variables considered. While the effect of motion dominates for brass instruments, string and woodwind instruments exhibit large note-related differences, which should be taken into account in virtual acoustic realities if an auditory liveliness comparable to physical reality is to be achieved.}, language = {en} } @article{AckermannBoehmBrinkmannetal.2019, author = {Ackermann, David and B{\"o}hm, Christoph and Brinkmann, Fabian and Weinzierl, Stefan}, title = {The Acoustical Effect of Musicians' Movements During Musical Performances}, series = {Acta Acustica united with Acustica}, volume = {105}, journal = {Acta Acustica united with Acustica}, number = {2}, publisher = {Hirzel}, issn = {1861-9959}, doi = {10.3813/AAA.919319}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-59024}, pages = {356 -- 367}, year = {2019}, abstract = {Acoustic musical instruments act as dynamic sound sources communicating the expressive intentions of a performer to the audience in a dedicated spatial environment. From an acoustical point of view, the directivity of musical instruments is relevant both for the loudness and timbre of an instrument at a certain position in the audience, as well as for the spatial characteristics of the generated sound field. Musical instruments, however, are dynamic sound sources always moved by musicians as an element of their performance on stage. This work aims at assessing the acoustical effect and the perceptual relevance of these movements. For this purpose, we have recorded solo musical performances with all standard orchestral instruments with an optical motion tracking system, as well as the corresponding audio signals. The effect of the movements was evaluated by analysing the spectral fluctuation and the time-dependence of room acoustical parameters in a virtual acoustic environment in anechoic and reverberant conditions. In a subsequent listening test, an auralization of the static and dynamic musical performance was presented to listeners by binaural synthesis, showing that the signal-related fluctuations are clearly audible both in anechoic and reverberant situations. We discuss different approaches how to consider these effects for the simulation of natural acoustic sources in virtual acoustic reality.}, language = {en} } @article{AckermannBrinkmannWeinzierl2024, author = {Ackermann, David and Brinkmann, Fabian and Weinzierl, Stefan}, title = {A Database with Directivities of Musical Instruments}, series = {Journal of the Audio Engineering Society}, volume = {72}, journal = {Journal of the Audio Engineering Society}, number = {3}, publisher = {Audio Engineering Society}, issn = {1549-4950}, doi = {10.17743/jaes.2022.0128}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-58923}, pages = {170 -- 179}, year = {2024}, language = {en} }