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The emerging audio formats for 3D rendering use several rendering methods and are dedicated for playback on various loudspeaker layouts defined by the Recommendation ITU-R BS.2051. The aim of this work is to investigate the perceptual properties when rendering point sources, with regard to extent, change in colouration, and continuity of
moving sou...
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... colouration experiment employed a pink noise sound moving along the trajectories shown in Fig. 5. The orange points represent the front trajectory, green represents the side trajectory, and blue the circular trajectory. The back-and-forth and circular motion trajectories took 2s. Participants were asked to compare the amount of timbral fluctuation in the moving sounds, to give 0 points if there is no change in timbre, 100 points ...
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This chapter describes the perceptual properties of auditory events, the sound images that we localize in terms of direction and width, when distributing a signal with different amplitudes to one or a couple of loudspeakers. These amplitude differences are what methods for amplitude panning implement, and they are also what mapping of any coinciden...
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... Theoretical predictions for inconsistencies in perceived source direction, extent, and spectral balance are presented in Section 3. Section 4 details a multiple stimulus method, used to collect ratings for seven systems reproduced over a periphonic nine-loudspeaker ITU-R BS.2051-1 [6] layout: all combinations of three rendering methods (VBAP, VBIP, and the dual-band approach) and two variants of the panning rule (standard and refined triangulation based on an 2 minimum constraint), as well as higherorder Ambisonics. A number of ratings were obtained following a similar methodology to [7], both for static and moving sources, testing consistency in predicted attributes. Results detailing differences between both the rendering systems and theoretical predictions are reported in Section 5 and discussed in Section 6, before findings are summarized in Section 7. ...
... This avoids ill-conditioning in the Ambisonics decoder, but also decouples the HOA order from the number of real loudspeakers. For the evaluation, following a similar method to [7], a virtual 70-loudspeaker t-design is used for second-order Ambisonic reproduction. ...
... The following takes a similar approach to [4,7], though predicts inconsistencies between low and mid-high frequency cues for a number of perceptual attributes for a single-band approach (illustrated in Fig. 4). In each case, predictions are for a plain single-band VBAP render over the 4+5+0 setup of Fig. 1. ...
Panning laws for multi-loudspeaker setups, for example vector base amplitude panning, are typically derived based on either low or high frequency assumptions. It is well known, however, that auditory cues for both localization and loudness differ at these frequencies. This paper investigates the use of dual-band panning, whereby low and high frequency gains and normalization are applied separately. Single- and dual-band rendering algorithms are described, with predicted theoretical localization, spectral balance, and source extent cues given. A multiple stimulus test is described, performed for a number of trajectories rendered to a periphonic nine-loudspeaker ITU-R BS.2051-1 setup, with rated attributes based on predicted sources of error. Results are reported, detailing differences between both theoretical predictions and systems under test.
... On the 4+5+0 3D layout [20], All-Round Ambisonic Decoding (AllRAD [10]) permits to use the order N = 5 to support its dense frontal loudspeaker spacing. This paper discusses AllRAD because of its practical simplicity and its option to insert and downmix imaginary loudspeakers [21,22,23] to stabilize loudness. And yet, its use with 5 th -order Ambisonics still yields a loudness difference of nearly +3 dB, when comparing loudnesses for panning to the back and to the front, see Fig. 1. ...
On ITU BS.2051 surround with height loudspeaker layouts, Ambisonic panning is practice-proof, when using AllRAD decoders involving imaginary loudspeaker insertion and downmix. And yet on the 4+5+0 layout, this still yields a loudness difference of nearly 3 dB when comparing sounds panned to the front with such panned to the back. AllRAD linearly superimposes a series of two panning functions, optimally sampled Ambisonics and VBAP. Both are perfectly energy-preserving and therefore do not cause the loudness differences themselves, but their linear superposition does. In this contribution we present and analyze a new AllRAD2 approach that achieves decoding of constant loudness by (i) superimposing the squares of both panning functions, and (ii) calculating the equivalent linear decoder of the square root thereof.
This habilitation outlines the scientific works and methods undertaken to free virtual acoustic rendering based on the spherical harmonic basis functions (Ambisonics) from excessive wiggles, blur or poor robustness, and efforts undertaken to liberate the rendering of measured or recorded virtual environments of interest from fixed source and receiver directivities, or source and receiver locations. As a collection of works, the habilitation attempts to provide context and an overview of the papers, works, software, the contributions to the book Ambisonics, and projects accomplished to realize these goals, in many cases within a collaborative effort with master and doctoral students, and esteemed colleagues. (Works collected here in are nearly all available per given URL or DOI links).
