{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T23:19:30Z","timestamp":1780615170779,"version":"3.54.1"},"reference-count":26,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2011,1,10]],"date-time":"2011-01-10T00:00:00Z","timestamp":1294617600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study shows that a small electret condenser microphone connected to a notebook or a personal computer (PC) has a prominent response in the extremely low frequency region in a specific environment. It confines most acoustic waves within a tiny air cell as follows. The air cell is constructed by drilling a small hole in a digital versatile disk (DVD) plate. A small speaker and an electret condenser microphone are attached to the two sides of the hole. Thus, the acoustic energy emitted by the speaker and reaching the microphone is strong enough to actuate the diaphragm of the latter. The experiments showed that, once small air leakages are allowed on the margin of the speaker, the microphone captured the signal in the range of 0.5 to 20 Hz. Moreover, by removing the plastic cover of the microphone and attaching the microphone head to the vibration surface, the low frequency signal can be effectively captured too. Two examples are included to show the convenience of applying the microphone to pick up the low frequency vibration information of practical systems.<\/jats:p>","DOI":"10.3390\/s110100623","type":"journal-article","created":{"date-parts":[[2011,1,12]],"date-time":"2011-01-12T04:53:33Z","timestamp":1294808013000},"page":"623-637","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Response Identification in the Extremely Low Frequency Region of an Electret Condenser Microphone"],"prefix":"10.3390","volume":"11","author":[{"given":"Yih-Nen","family":"Jeng","sequence":"first","affiliation":[{"name":"Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 70701, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tzung-Ming","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 70701, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shang-Yin","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 70701, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2011,1,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1200","DOI":"10.1121\/1.385701","article-title":"Analysis of the acoustic response of circular electret condenser microphones","volume":"69","author":"Zahn","year":"1981","journal-title":"Acoust. Soc. Am. J"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/S0924-4247(02)00137-1","article-title":"Silicon condenser microphones with corrugated silicon oxide\/nitride electret membranes","volume":"100","author":"Kressmann","year":"2001","journal-title":"Sens. Actuat. A"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3179","DOI":"10.1121\/1.1572147","article-title":"Background noise in piezoresistive, electret condenser, and ceramic microphones","volume":"113","author":"Zuckerwar","year":"2003","journal-title":"Acoust. Soc. Am. J"},{"key":"ref_4","unstructured":"Edgar, P (1998). Sensors for Measurement and Control, Longman."},{"key":"ref_5","unstructured":"Sinclair, I (2001). Sensors and Transducers, Newnes, Butterworth-Heinemann. [3rd ed]."},{"key":"ref_6","unstructured":"Wilson, J.S. (2005). Sensors Technology Handbook, Newnes, Elsevier Inc."},{"key":"ref_7","unstructured":"Huber, D.M., and Runstein, R.E. (2005). Mordern Recording Techniques, Focal Press. [6th ed]."},{"key":"ref_8","unstructured":"Jeng, Y.N., and Lee, S.Y. (, January April). Qualitative Frequency Response Calibration of Sonocardiography System to Sense Wrist Pulse. Beijing, China."},{"key":"ref_9","unstructured":"Jeng, Y.N., Yang, T.M., Cheng, Y.C., and Huang, J.M. (, January June). Acoustic Data Analysis of Remote Control Vehicles via Fourier Sine Spectrum and Spectrogram. Seattle, Washington, DC, USA."},{"key":"ref_10","unstructured":"Jeng, Y.N., Yang, T.M., and Wu, C.H. (, January January). Low Frequency Analysis of Acoustic and Vibration Data of a Remote Control Electronic Helicopter. Orlando, FL, USA."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1088\/0964-1726\/9\/6\/320","article-title":"The frequency response of magnetoelastic sensors to stress and atmospheric pressure","volume":"8","author":"Kouzoudis","year":"2000","journal-title":"Smart. Mater. Struct"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/S0924-4247(97)01532-X","article-title":"A silicon condenser microphone with polyimide diaphragm and backplate","volume":"63","author":"Pedersen","year":"1997","journal-title":"Sens. Actuat. A"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"313","DOI":"10.3390\/s100100313","article-title":"Improving the response of accelerometers for automotive applications by using LMS adaptive filters","volume":"10","author":"Hernandez","year":"2010","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1023\/A:1000566921106","article-title":"A practical example of low frequency and trend removal","volume":"86","author":"Ress","year":"1998","journal-title":"Bound-Lay. Meteorol"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"036705","DOI":"10.1103\/PhysRevE.75.036705","article-title":"Automatic algorithm for monotone trend removal","volume":"75","author":"Vaomos","year":"2007","journal-title":"Phys. Rev. E"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1007\/BF00226078","article-title":"Modeling lumber strength spatial variation using trend removal and kriging analysis","volume":"26","author":"Lam","year":"1992","journal-title":"Wood. Sci. Technol"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2780","DOI":"10.1149\/1.1838714","article-title":"Analysis of electrochemical noise by power spectral density applied to corrosion studies","volume":"145","author":"Bertocci","year":"1998","journal-title":"J. Electrochem. Soc"},{"key":"ref_18","unstructured":"Brigham, E.O. (1988). The Fast Fourier Transform and Its Applications, Prentice Hall."},{"key":"ref_19","unstructured":"Carmona, R., Hwang, W.L., and Torr\u00e9sani, B (1998). Practical Time-frequency Analysis: Gabor & Wavelet Transforms with an Implementation in S, Academic Press."},{"key":"ref_20","unstructured":"Goswami, J.C., and Chan, A.K. (1999). Fundamentals of Wavelets, Theory, Algorithms, and Application, John Wiley & Sons, Inc."},{"key":"ref_21","first-page":"1","article-title":"Wavelet bicoherence: A new turbulence analysis tool","volume":"2","author":"Sanchez","year":"1995","journal-title":"Phys. Plasmas"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Mallat, S.G. (1999). A Wavelet Tour of Signal Processing, Academic Press. [2nd ed].","DOI":"10.1016\/B978-012466606-1\/50008-8"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1146\/annurev.fl.24.010192.002143","article-title":"Wavelet transforms and their applications to turbulence","volume":"24","author":"Farge","year":"1992","journal-title":"Annu. Rev. Fluid Mech"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Boashash, B (1992). Time-frequency Signal Analysis, Methods and Application, Longman.","DOI":"10.2307\/2532288"},{"key":"ref_25","first-page":"1673","article-title":"Decomposition of one-dimensional waveform using iterative Gaussian diffusive filtering methods","volume":"464","author":"Jeng","year":"2008","journal-title":"Proc. R. Soc. Lond. A"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1137\/0730004","article-title":"Accurate monotone cubic interpolation","volume":"30","author":"Huynh","year":"1993","journal-title":"SIAM. J. Numer. 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