by National Aeronautics and Space Administration, Scientific and Technical Information Branch in [Washington, D.C.?] .
Written in English
|Statement||Allan J. Zuckerwar, Roger W. Meredith.|
|Series||NASA reference publication ;, 1128|
|Contributions||Meredith, Roger W., United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.|
|LC Classifications||QC233 .Z83 1984|
|The Physical Object|
|LC Control Number||85600806|
The sound absorption coefficient for metal foams at different frequencies increase with their thickness .With thickening of the porous body, the pore channels are extended and then cause more energy loss. It is also found that the peak of sound absorption coefficient will move to the low-frequency range for thicker porous bodies. This bass sound absorber is great for industrial, architectural or pro audio applications. Machinery and mechanical rooms. For harsh noisy environments that require high performance, low frequency noise reduction. Above acoustical ceiling grid systems. This low frequency absorber user friendly alternative to glass fiber insulations. The idea of localized resonance in phononic crystals is introduced to improve the low-frequency acoustic absorption of viscoelastic materials, which are widely used underwater to absorb the. Absorbing low frequency sound is a big job, or at least, a job for big things. Acoustic absorption systems require big resonant cavities with large amounts of heavy damping material and.
Sponsor a Book. Absorption of sound 33 works Search for books with subject Absorption of sound. Search. Low-frequency sound absorption measurements in air Low-frequency sound absorption measurements in air Allan J Zuckerwar Read. Sound absorbent materials Mary A. Vance Read. Read. Read. Impedance measurements of acoustic duct liners. A particular structure that consists of four parallel-arranged perforated panel absorbers (PPAs) is proposed for the low frequency sound absorption within a constraint space. The apertures of the perforated panels are set to ≥ mm, and the number of orifices is much less and therefore easier to be produced in comparison with that of the micro perforated panel (MPP).Author: Xin Li, Qianqian Wu, Ludi Kang, Bilong Liu. The model is verified by a Boundary Element Method simulation, scale measurements and live concert measurements. A new live measurement method is developed to evaluate the low frequency sound pressure level distribution without disturbing the ongoing tonyasgaapartments.com: Elena D. Shabalina, Michael Vorländer. Jan 23, · Very low frequency absorption. hz down to 30hz? Hi, although causing some difference in the sound coming from the left and right loudspeakers, has really improved things. I haven't done measurements yet with the trap in place - I only have the original measurements before any treatment though. Share Quote.
This chapter introduces the principles of sound absorbers and the factors that affect acoustic absorption. The basic wave phenomena related to sound propagation such as acoustic reflection Author: Xiaojun Qiu. Sep 20, · When it comes to low-frequency sound waves, traditional sound-absorbing materials tend to be undesirably bulky, heavy or thick. Now, researchers have . Sound - Sound - Sound absorption: In addition to the geometric decrease in intensity caused by the inverse square law, a small part of a sound wave is lost to the air or other medium through various physical processes. One important process is the direct conduction of the vibration into the medium as heat, caused by the conversion of the coherent molecular motion of the sound wave into. Reasons for focusing on aircraft noise low-frequency components were: as low-frequency sound encounters less absorption as it travels through the air than higher frequency sound, it persists for longer distances; the amount of sound transmitted from the outside to the inside of buildings is greater at low than at high frequencies.