Vertaile menetelmiä

	Akustinen holografia	Impedanssitutkimusputki
Tieteenala	Akustiikka	Akustiikka
Menetelmäperhe	Process / pipeline	Process / pipeline
Syntyvuosi	1985	1866
Kehittäjä	James Maynard, Earl Williams, Yongjian Lee	August Kundt
Tyyppi	Sound field reconstruction method	Acoustic absorption measurement
Alkuperäislähde	Maynard, J. D., Williams, E. G., & Lee, Y. (1985). Near-field acoustic holography: I. Theory of generalized holography and the development of NAH. Journal of the Acoustical Society of America, 78(4), 1395–1413.	ASTM E1050-19 (2019). Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube, Two Microphone and a Digital Frequency Analysis System. American Society for Testing and Materials.
Rinnakkaisnimet	NAH, near-field acoustics, sound field mapping, acoustic imaging	kundt tube, resonance tube, acoustic absorption, sound absorption coefficient
Liittyvät	5	5
Tiivistelmä	Near-Field Acoustic Holography (NAH) is a technique for reconstructing 3D acoustic sound fields and visualizing sound radiation from sources by measuring pressure at a dense microphone array in the near field. Pioneered by Maynard, Williams, and Lee in 1985, NAH extends holographic principles from optics to acoustics, enabling detailed acoustic source characterization, noise source identification, and acoustic field visualization that is impossible with conventional single-point or line-array methods.	An impedance tube (or Kundt tube) is a laboratory apparatus for measuring the acoustic absorption coefficient and surface impedance of materials. Originally developed by August Kundt in 1866, the technique has been standardized by ASTM and ISO for characterizing noise-control and acoustic-treatment materials. The impedance tube method is simple, portable, and cost-effective, making it the industry standard for pre-design acoustic material selection and quality control.