A slender store hanging under a fighter wing sits in an acoustic field near 164 dB overall. A wind chime tube hanging from a porch beam sits in an acoustic field near 40 dB. The store is asked to survive; the chime is asked to… Read more
The Barrett scaling law is one of the oldest tools in the launch vehicle random vibration toolbox, and it is still one of the most used. It answers a question that comes up on every new program before a single accelerometer has been mounted: I… Read more
Cut a rectangular hole in an aerodynamic surface and fly it at high subsonic or supersonic speed, and the hole will sing. Not quietly. Overall sound pressure levels inside a fighter weapon bay routinely exceed 160 dB, and the energy is not spread evenly across… Read more
The Problem Here is a problem that comes up more often than the standards would suggest. An engineer is deriving a random vibration maximum predicted environment (MPE) for launch vehicle components mounted very close to the engines. Accelerometer data from engine test stand and stack… Read more
Skyscraper design was once governed almost entirely by strength — could the frame carry gravity, wind and seismic loads with adequate margin? For the new generation of ultra-slender “pencil towers,” the governing requirement has shifted to something more subtle: occupant comfort. A building can be… Read more
The data center construction boom has made a 24/7 mechanical plant into everyone’s new neighbor — and the acoustics run in both directions: noise radiating out to the community, and noise and vibration attacking the equipment inside. Driven by cloud computing and AI, data centers… Read more
By Tom Irvine The spruce soundboard of a concert grand piano and the sheet-steel housing of an industrial gearbox have more in common than their outward appearances suggest. Both are thin panels driven into vibration by an internal source. Both radiate sound into the surrounding… Read more
At John Wayne Airport (SNA) in Orange County, California, noise abatement on departures is managed through a combination of specialized Noise Abatement Departure Procedures (NADPs), strict regulatory limits, and operational constraints. Because SNA is located in a densely populated, noise-sensitive residential area, the airport enforces… Read more
Tapiola Lutheran Church in Espoo, Finland, Opened in 1965 Helmholtz-type resonators are built into the walls of the church. The slots between brick pairs and cavities behind them act as both absorbers and diffusors of sound. The absorption reduces the reverberation time as desired for… Read more
A sound file from the attack on the U.S. Embassy in Cuba has now been made available on the Internet. I did a spectral analysis of this file using my Matlab GUI scripts. The sound source is still unknown. The attacks have caused hearing, cognitive,… Read more