From the BBC website yesterday:
“Researchers have filmed a shock wave coming from a trombone for the first time. Shock waves are a special kind of pressure wave, which can sometimes even exceed the speed of sound. The idea that trombones create weak shock waves was first put forward in 1995, but only now has the process been filmed. The video was revealed at the American Acoustical Society’s meeting in Seattle, US.”
There was also a nice ARTICLE earlier this week about CHLADNI patterns on stringed instruments. Plenty of nice bedtime reading there!
(Source: http://www.bbc.co.uk/)