• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.495-498
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• 2004

핸드폰등에 사용되고 있는 마이크로스피커를 개발하는 과정에서 마이크로스피커의 진동특성과 음향특성 을 전산해석하였다. 해석과정에서 기초 데이터를 얻기 위하여 하이브리드 방법을 이용하여 각 부품들의 제원 및 마이크로스피커 모델링을 위한 매개변수들을 규명하였다. 전산 해석 결과와 측정한 전기 임피던스 및 음향 응답특성은 잘 일치함을 보였다. 또한, 진동특성을 분석하여 각 주파수에서의 다이아프램의 변위등 진동특성을 분석하여 다이아프램등의 형상에 따른 이상 진동현상 등을 파악할 수 있었다. 전산해석 방법을 이용하면 최적 음향특성을 위한 마이크로스피커의 다이아프램 형상 및 전자기 회로 개선에 사용할 가능성을 알 수 있었다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.499-500
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• 2004

일반적으로 진동판의 크기와 형태는 스피커의 음파 방출 효율과 재생대역 및 왜곡특성을 결정하는 중요한 요인이다. 지금까지 대부분의 연구결과들은 직경 25mm 이상, 두께 0.1mm 이상의 다양한 소재의 진동판으로 이루어진 스피커들을 대상으로 하였다. 그러나 현재 수요가 급증하고 있는 마이크로스피커에 사용되는 진동판들은 직경이 20mm 이하이고, 그 두께는 수십 ${\mu}m$ 필름 소재를 사용하고 있다. 이러한 이유로 마이크로스피커의 동작특성은 일반적인 스피커에 비해 재생대역이 좁고, 고조파 왜가 크게 나타난다. 본 논문은 수 십 ${\mu}m$ 두께의 필름 진동판을 사용하는 마이크스피커의 설계 시, 기본적인 특성을 예측할 수 있도록 하기 위해 진동판의 두께 변화, 단면의 곡률변화에 따른 스피커의 특성 변화를 조사하였다.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1131-1138
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• 2003

Active noise control(ANC) is an approach to noise reduction in which a secondary noise source destructively interferes with the unwanted noise is introduced. Generally, the performance of ANC is determined how well a secondary noise tracks noises. A secondary noise is generated from the cancelling speaker and a error sensor pick up error signal. The transfer function between the cancelling speaker and the error sensor is not flat and distorts secondary noises. Consequently, the performance of ANC is degraded by the transfer function. In this paper, a single sensor ANC which considers the characteristics of the speaker and the error sensor is proposed. To reduce distortion of secondary noises, the transfer function is estimated by adaptive inverse modelling and the primary noises are estimated by Kalman filter. Experimental results show that the proposed single sensor ANC effectively attenuates noises.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.333-336
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• 2017

A speaker diaphragm generates a divided vibration. The influence of the break-up mode is sufficient to cause a shape change in the diaphragm. In this paper, is widely used in ultra-thin multi-media devices, including smart phones is the advance guard of the IT sector, the micro-speakers and its target. Micro-speakers are different from general speakers. The plate has structural form and space constraints. In particular, they utilize a closed-type drive space. It is difficult to provide cooling for the auxiliary suspension structure because of the heat generated in the moving coil. The present study considered the relationship between the break-up mode and the heat transfer of the diaphragm. An experiment was conducted in two stages to compare the embodiment of the break-up mode and heat transfer in a certain frequency range. The changes in the heat were determined through measurements and thermal imaging of the break-up mode. The break-up mode tendency of the diaphragm could be rapidly predicted based on the imaging results using the thermal imaging camera. This will help in the optimal design of micro-speakers.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.7
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• pp.525-536
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• 2014

In this paper, GUI program for microspeaker system simulation program was developed and verified through closed box, vent box and 6th order bandpass enclosure system. By using the pseudo loudspeaker model concept, TS parameters and rear volume of microspeaker were identified. Their suitabilities were proved by comparing test results with simulations of electrical impedance and sound pressure response curves for the three box types; closed box, vent box and 6th order bandpass box. Also, MSSP was found to be effective regardless of the microspeaker's shape, either circular or rectangular shape. MSSP can be used for the microspeaker system simulation, and can give a general prediction of such as; sound pressure level curve, electrical impedance, diaphragm velocity and displacement curve according to multiple design parameters; diaphragm mass, compliance, force factor, front and rear volume, front and rear port's diameter and length.

• The Journal of the Acoustical Society of Korea
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• v.25 no.3
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• pp.101-106
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• 2006

In this study, the impedance behavior of micro-speaker had been investigated as a function of hole area existing on the grille. In order to theoretically study the change of acoustical property due to the different total hole area, the holes were treated as a short open pipe system, such as an orifice. This theoretical result was in an excellent agreement with the experimental one. In detail, the acoustic impedance to be caused by the hole could be greatly increased with the decrease of hole area. Therefore, it can be concluded that the acoustic property of micro-speaker could be greatly changed by increasing the acoustic impedance of hole with reducing hole area.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.17-18
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• 2019

최근 4차 산업혁명의 핵심 분야 중 하나인 인공지능에 대한 많은 연구가 이루어지고 있다. 많은 기업들이 인공지능 스피커와 같은 제품을 출시하고 있으나 대부분 비서 역할만을 할 수 있도록 구성된 제품이 대부분이다. 그러나 학교와 같이 많은 사람이 존재하는 경우 시끄러운 환경에서 사용되고 있는 인공지능 스피커는 명령 인식이 제대로 되지 않아 실용도가 저하되는 단점을 가지고 있으며, 현재 인공지능 스피커는 단순한 질의응답 수준의 응대만 가능하여 다소 부족한 부분이 있다. 또한 인공지능의 급속한 발전으로 인공지능 스피커가 아닌 전자제품에 인공지능 비서 기능이 탑재된 제품도 새롭게 출시되어 인공지능 스피커가 필요 없을 수도 있기에, 본 논문에서는 학교와 같은 주변의 소음이 많이 발생하는 교육 환경에서도 소통이 가능한 인공지능 마이크를 활용할 수 있는 모델을 제안한다.

• The Journal of the Acoustical Society of Korea
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• v.26 no.3
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• pp.115-122
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• 2007

In this study, the property and the structure of micro-speaker had been firstly shown to be treated as a ducted speaker-system, which was consisted of the unit and the ducted enclosure. With the decrease of total hole area. the resonance frequency of micro-speaker was decreased due to increasing the stiffness or reducing the compliance. The behavior of resonance frequency relative to the total hole area was exactly agreed with that of the square root of compliance. With decreasing the total hole area. the effective chamber volume was increased, but the reference sound pressure level was exponentially reduced in the low and middle frequency range.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1112-1118
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• 2007

It was discussed to identify Thiele Small Parameters for Pseudo loudspeaker within 10mm grade microspeaker attached to closed-box using known dynamic mass of moving parts. Also, enhanced circuit model for vented-box micro speaker system was used to more accurately simulate electrical impedance curves for real vented-box microspeaker system and compared to test results. Consequently, it showed that micro speaker could be modeled by pseudo loudspeaker TS parameters similar to general loudspeaker. Vented-box microspeaker model with pseudo loudspeaker TS parameters was well suited to describe real microspeaker. Also, it was proposed to estimate volume of rear closed-box of microspeaker without design specifications.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.341-346
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• 2007

The purpose of this paper is to propose the design of VADSM(Value-Added Digital Speaker Module) which tunes up the speaker unit by measuring the speaker's frequency responses and controlling EQ band. This module can reduce audible distortions at particular frequency band and improve some flatness in the speaker's frequency response. VADSM is composed of DSP AMP and speaker unit. When a speaker transforms electrical signal to sound, the magnitude response at some frequencies are more or less than normal level. So, DSP AMP can be used to adjust those magnitudes up or down by controlling its EQ bands.