Near-sound-field propagation based on individual beam-steering for carrier and sideband waves with parametric array loudspeaker

2016 ◽  
Author(s):  
Masato Nakayama ◽  
Ryosuke Konabe ◽  
Takahiro Fukumori ◽  
Takanobu Nishiura
Keyword(s):  
Beam Steering ◽  
Sound Field ◽  
Parametric Array

Practical method for parametric array source evaluation at 120 kHz frequency range in the near-field region

2020 ◽  
Vol 68 (5) ◽  
pp. 389-398
Author(s):  
Hongmin Ahn ◽  
Yonghwan Hwang ◽  
Yub Je ◽  
Wonkyu Moon
Keyword(s):  
Near Field ◽  
Sound Field ◽  
Simulated Data ◽  
Practical Method ◽  
Difference Frequency ◽  
Water Tank ◽  
Small Aperture ◽  
Frequency Wave ◽  
Parametric Array ◽  
The Difference

A parametric array is a non-linear conversion process that can generate a narrow beam of low-frequency sound with a small aperture. One of the challenging issues with a parametric array is precise measurement of the sound field generated. In particular, near the transducer, it is not easy to measure the sound field generated by a parametric array precisely, because the amplitude of the difference frequency wave is much lower than the amplitude of the primary wave. In this study, the practical issues that should be considered in the design of near-distance experiments with a parametric array are examined. Limiting effects were examined, and their associated characteristics were identified by numerical simulations. Experiments were performed in a water tank (18 x 12 x 10 m) to assess these characteristics, using a custom-designed acoustic filter; the beam pattern and propagation curve of the difference frequency wave generated by the parametric array were measured and compared with simulated data.

3-D sound field reproduction with reverberation control on surround sound system by combining parametric and electro-dynamic loudspeakers

2021 ◽  
Vol 263 (5) ◽  
pp. 1083-1094
Author(s):  
Yuna Harada ◽  
Kenta Iwai ◽  
Masato Nakayama ◽  
Takanobu Nishiura
Keyword(s):  
Sound Field ◽  
Experimental Results ◽  
Reverberation Time ◽  
Video Technology ◽  
Sound System ◽  
Target Sound ◽  
Surround Sound ◽  
Sound Image ◽  
Parametric Array ◽  
Conventional Systems

Recently, with the development of video technology, 3-D sound field reproduction systems that can provide a high presence have attracted attention. Conventional systems with electro-dynamic loudspeakers have a problem that the sound image lacks sharpness when constructing a narrow sound image. To solve this problem, we utilize a parametric array loudspeaker which has sharp directivity by the straightness of ultrasounds. Parametric array loudspeakers can produce sharper sound images due to the sharper directivity and lower reverberation compared with electro-dynamic loudspeakers. However, it is difficult to represent reverberation by parametric array loudspeakers. In this paper, we propose a method for 3-D sound field reproduction to achieve both the sharp images and reverberation presence by combing parametric array loudspeakers and electro-dynamic loudspeakers in surround sound system. In the proposed method, sharp sound images are rendered by parametric array loudspeakers and the reverberation presence is provided by electro-dynamic loudspeakers, emitting reverberation signals synthesized with a reverberation control filter. The reverberation control filter is adaptively designed to reproduce the reverberation time and the direct-to-reverberation ratio of the target sound field in other environments. The experimental results show that the proposed method can achieve the reproducing the sharp sound image with some reverberation presence.

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