Cancellation of room reflections over an extended area using Ambisonics

Lecomte, P.; Gauthier, Philippe‐Aubert; Langrenne, Christophe; Berry, Alain; Garcia, Alexandre

doi:10.1121/1.5023326

Cited by 9 publications

(4 citation statements)

References 25 publications

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“…Spatial filters in HOA domain can also be implemented to further edit the sound scene (e.g. directional filtering [39], or room equalization [40]).…”

Section: Spatial Audio Formatsmentioning

confidence: 99%

Acoustic research for telecoms: bridging the heritage to the future

Nicol,

Monfort

2023

Acta Acust.

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In its early age, telecommunication was focused on voice communications, and acoustics was at the heart of the work related to speech coding and transmission, automatic speech recognition or speech synthesis, aiming at offering better quality (Quality of Experience or QoE) and enhanced services to users. As technology has evolved, the research themes have diversified, but acoustics remains essential. This paper gives an overview of the evolution of acoustic research for telecommunication. Communication was initially (and for a long time) only audio with a monophonic narrow-band sound (i.e. [300–3400 Hz]). After the bandwidth extension (from the wide-band [100–7000 Hz] to the full-band [20 Hz–20 kHz] range), a new break was the introduction of 3D sound, either to provide telepresence in audioconferencing or videoconferencing, or to enhance the QoE of contents such as radio, television, VOD, or video games. Loudspeaker or microphone arrays have been deployed to implement “Holophonic” or “Ambisonic” systems. The interaction between spatialized sounds and 3D images was also investigated. At the end of the 2000s, smartphones invaded our lives. Binaural sound was immediately acknowledged as the most suitable technology for reproducing 3D audio on smartphones. However, to achieve a satisfactory QoE, binaural filters need to be customized in relation with the listener’s morphology. This question is the main obstacle to a mass-market distribution of binaural sound, and its solving has prompted a large amount of work. In parallel with the development of technologies, their perceptual evaluation was an equally important area of research. In addition to conventional methods, innovative approaches have been explored for the assessment of sound spatialization, such as physiological measurement, neuroscience tools or Virtual Reality (VR). The latest development is the use of acoustics as a universal sensor for the Internet of Things (IoT) and connected environments. Microphones can be deployed, preferably with parcimony, in order to monitor surrounding sounds, with the goal of detecting information or events thanks to models of automatic sound recognition based on neural networks. Applications range from security and personal assistance to acoustic measurement of biodiversity. As for the control of environments or objects, voice commands have become widespread in recent years thanks to the tremendous progress made in speech recognition, but an even more intuitive mode based on direct control by the mind is proposed by Brain Computer Interfaces (BCIs), which rely on sensory stimulation using different modalities, among which the auditory one offers some advantages.

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“…Spatial filters in HOA domain can also be implemented to further edit the sound scene (e.g. directional filtering [39], or room equalization [40]).…”

Section: Spatial Audio Formatsmentioning

confidence: 99%

Acoustic research for telecoms: bridging the heritage to the future

Nicol,

Monfort

2023

Acta Acust.

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“…Crossover filters have also a role in the control of satellite speakers and subwoofers in the NASA Exterior Effects Room, which allows the 3D reproduction of recorded aircraft flyover sounds [158]. Splitting of different Ambisonic orders to appropriate frequency bands in a 3D sound reproduction with roomreflection compensations has been tested using crossover filters [159]. Winter et al have implemented the wave field synthesis by running the full system only at low frequencies and a local approximation at high frequencies, combining the two bands with a crossover network [160].…”

Section: Other Applications Of Crossover Filtersmentioning

confidence: 99%

Crossover Networks: A Review

Cecchi,

Bruschi,

Nobili

et al. 2023

J. Audio Eng. Soc.

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Crossover networks for multi-way loudspeaker systems and audio processing are reviewed, including both analog and digital designs. A high-quality crossover network must maintain a flat overall magnitude response, within small tolerances, and a sufficiently linear phase response. Simultaneously, the crossover filters for each band must provide a steep transition to properly separate the bands, also accounting for the frequency ranges of the drivers. Furthermore, crossover filters affect the polar response of the loudspeaker, which should vary smoothly and symmetrically in the listening window. The crossover filters should additionally be economical to implement and not cause much latency. Perceptual aspects and the inclusion of equalization in the crossover network are discussed. Various applications of crossover filters in audio engineering are explained, such as in multiband compressors and in effects processing. Several methods are compared in terms of the basic requirements and computational cost. The results lead to the recommendation of an all-pass-filter-based Linkwitz-Riley crossover network, when a computationally efficient minimum-phase solution is desired. When a linear-phase crossover network is selected, the throughput delay becomes larger than with minimum-phase filters. Digital linear-phase crossover filters having a finite impulse response may be designed by optimization and implemented efficiently using a complementary structure.

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“…Digital technology has lead to attempts to invert impulse responses accurately, and reduce time distortion, for example [1; 2; 3]. Sound field synthesis methods, using many loudspeakers, have been used to cancel reflections within a region [4] and even exploit reflections to directly provide additional source freedom for target reproduction [6]. For a recent extensive recent review of room compensation methods see [5].…”

Section: Introductionmentioning

confidence: 99%

A Room Compensation Method by Modification of Reverberant Audio Objects

Menzies

Coleman

Fazi

2021

IEEE/ACM Trans. Audio Speech Lang. Process.

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Conventional channel-based room equalisation can reduce overall colouration caused by the room response, however it cannot separately correct the colouration caused by the late and early parts of the response, or consider the reverberance in the source signal. A room compensation method is developed here for a source signal in which the dry source sound and the associated target reverberant response are encoded separately, which is possible in an object-based audio framework. The target response is modified using the reproduction room response. Subject to some conditions the combined response approximates the target, with accurate early and late equalisations, reverberant balance, and decay timing. Stochastic assumptions are used to simplify the processing, enabling efficient real-time processing of the encoded audio.

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Cancellation of room reflections over an extended area using Ambisonics

Cited by 9 publications

References 25 publications

Acoustic research for telecoms: bridging the heritage to the future

Acoustic research for telecoms: bridging the heritage to the future

Crossover Networks: A Review

A Room Compensation Method by Modification of Reverberant Audio Objects

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