Highlights from the International Congress on Acoustics

Audio zones in cars

Using modified speakers in a car’s headrests and a new way to filter sound, Jordan Cheer and Stephen Elliott at the University of Southampton in England have created distinct listening zones for the front and back seats of a car. The team replaced the wooden backs of speakers with rectangles of metal gauze to focus sound toward passengers’ ears. Altering the volume and time delay of certain sounds confined sounds to particular zones in a car, Cheer said June 3. The system let drivers and passengers riding in the back listen to two similar pop songs at once, Cheer said. But during tests using something like white noise, some sounds from the rear still made it through to the front.

Skull music

Skull size, density and shape can influence the musical keys people hate, cognitive scientist Jitwipar Jitney Suwangbutra of William Paterson University in Wayne, N.J. reported June 4. Sounds vibrate slightly differently depending on the shape of a person’s skull, Suwangbutra said, which may affect how people perceive music. Suwangbutra and colleagues had 16 men and women listen to piano melodies in each of the 12 major keys and rate each song. The team measured the vibration patterns of participants’ skulls by tapping their heads with a microphone. People with similar-sized skulls tended to dislike the same melodies; for example, people with bigger skulls couldn’t stand the keys with higher frequencies.