A subband implementation of a multichannel and multiple position adaptive room response equalizer

Cecchi, Stefania; Terenzi, Alessandro; Bruschi, Valeria; Carini, Alberto; Orcioni, Simone

doi:10.1016/j.apacoust.2020.107702

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…Room inverse filters, whose purpose is to flatten the magnitude response of a loudspeaker in a specific room, have been studied extensively in the past 40 years [7][8][9][10]. A least-mean-squares or direct inversion of the room impulse response can be performed to arrive at a non-parametric room equalization design, in which autoregressive-moving average modeling can be used for a parametric model [11].…”

Section: Introductionmentioning

confidence: 99%

Loudspeaker Equalization for a Moving Listener

Lindfors¹,

Liski²,

Välimäki³

2022

J. Audio Eng. Soc.

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When a person listens to loudspeakers, the perceived sound is affected not only by the loudspeaker properties but also by the acoustics of the surroundings. Loudspeaker equalization can be used to correct the loudspeaker-room response. However, when the listener moves in front of the loudspeakers, both the loudspeaker response and room effect change. In order for the best correction to be achieved at all times, adaptive equalization is proposed in this paper. A loudspeaker-correction system using the listener's current location to determine the correction parameters is proposed. The position of the listener's head is located using a depthsensing camera, and suitable equalizer settings are then selected based on measurements and interpolation. After correcting for the loudspeaker's response at multiple locations and changing the equalization in real time based on the user's location, a loudspeaker response with reduced coloration is achieved compared to no calibration or conventional calibration methods, with the magnitude-response deviations decreasing from 10.0 to 5.6 dB within the passband of a high-quality loudspeaker. The proposed method can improve the audio monitoring in music studios and other occasions in which a single listener is moving in a restricted space.

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Section: Introductionmentioning

confidence: 99%

Loudspeaker Equalization for a Moving Listener

Lindfors¹,

Liski²,

Välimäki³

2022

J. Audio Eng. Soc.

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“…In that case, the high order filters can be replaced by a set of shorter subband filters in the subbands of the filter bank. This approach is usually called subband filtering, and it has been used in applications such as room equalization [101,113], echo cancellation [114,115], and active noise control [116,117], among others. In this work, we study the use of subband filtering for PSZ systems.…”

Section: Filter Bank Theorymentioning

confidence: 99%

Filter Optimization for Personal Sound Zones Systems

Cases¹

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Personal Sound Zones (PSZ) systems deliver different sounds to a number of listeners sharing an acoustic space through the use of loudspeakers together with signal processing techniques. These systems have attracted a lot of attention in recent years because of the wide range of applications that would benefit from the generation of individual listening zones, e.g., domestic or automotive audio applications. A key aspect of PSZ systems, at least for low and mid frequencies, is the optimization of the filters used to process the sound signals. Different algorithms have been proposed in the literature for computing those filters, each exhibiting some advantages and disadvantages. In this work, the state-of-the-art algorithms for PSZ systems are reviewed, and their performance in a reverberant environment is evaluated. Aspects such as the acoustic isolation between zones, the reproduction error, the energy of the filters, and the delay of the system are considered in the evaluations. Furthermore, computationally efficient strategies to obtain the filters are studied, and their computational complexity is compared too. The performance and computational evaluations reveal the main limitations of the state-of-the-art algorithms. In particular, the existing solutions can not offer low computational complexity and at the same time good performance for short system delays. Thus, a novel algorithm based on subband filtering that mitigates these limitations is proposed for PSZ systems. In addition, the proposed algorithm offers more versatility than the existing algorithms, since different system configurations, such as different filter lengths or sets of loudspeakers, can be used in each subband. The proposed algorithm is experimentally evaluated and tested in a reverberant environment, and its efficacy to mitigate the limitations of the existing solutions is demonstrated. Finally, the effect of the target responses in the optimization is discussed, and a novel approach that is based on windowing the target responses is proposed. The proposed approach is experimentally evaluated in two rooms with different reverberation levels. The evaluation results reveal that an appropriate windowing of the target responses can reduce the interference level between zones.

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A New Efficient Multi-Channel Fast NLMS (MC-FNLMS) Adaptive Algorithm for Audio Teleconferencing systems

Zerouali,

Djendi

2024

Physical Communication

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A subband implementation of a multichannel and multiple position adaptive room response equalizer

Cited by 4 publications

References 24 publications

Loudspeaker Equalization for a Moving Listener

Loudspeaker Equalization for a Moving Listener

Filter Optimization for Personal Sound Zones Systems

A New Efficient Multi-Channel Fast NLMS (MC-FNLMS) Adaptive Algorithm for Audio Teleconferencing systems

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