Reverberation steering and listening area expansion on 3-D sound field reproduction with parametric array loudspeaker

2014 ◽  
Author(s):  
Daisuke Ikefuji ◽  
Hideya Tsujii ◽  
Shohei Masunaga ◽  
Masato Nakayama ◽  
Takanobu Nishiura ◽  
...  
Keyword(s):  
Sound Field ◽  
Parametric Array ◽  
Area Expansion

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.

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

Modified Earpieces and CROS for High Frequency Hearing Losses

1968 ◽  
Vol 11 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Elizabeth Dodds ◽  
Earl Harford
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Field ◽  
Intensity Level ◽  
Test Results ◽  
High Frequency Hearing Loss ◽  
Increased Sensitivity ◽  
Difficult Cases

Persons with a high frequency hearing loss are difficult cases for whom to find suitable amplification. We have experienced some success with this problem in our Hearing Clinics using a specially designed earmold with a hearing aid. Thirty-five cases with high frequency hearing losses were selected from our clinical files for analysis of test results using standard, vented, and open earpieces. A statistical analysis of test results revealed that PB scores in sound field, using an average conversational intensity level (70 dB SPL), were enhanced when utilizing any one of the three earmolds. This result was due undoubtedly to increased sensitivity provided by the hearing aid. Only the open earmold used with a CROS hearing aid resulted in a significant improvement in discrimination when compared with the group’s unaided PB score under earphones or when comparing inter-earmold scores. These findings suggest that the inclusion of the open earmold with a CROS aid in the audiologist’s armamentarium should increase his flexibility in selecting hearing aids for persons with a high frequency hearing loss.

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