Sound solution

The world is getting noisier. Aircraft and traffic din, burglar and car alarms and loud music are all intrusive and impossible to block out completely. Even double glazing is not a perfect solution; it will cut out high frequencies, but the low-frequency thrum at the bass end of the sonic spectrum will still get through.

Now help for sleepless residents and perpetually disturbed office workers could be on the way. Researchers working on materials at the

in Darmstadt have devised a window that not only blocks out high and low-frequency noises but also actively cancels them out.

Sound waves are patterns of pressure transmitted through the air. When the pressure waves hit a building they cause it to vibrate and these waves are transmitted through the fabric of the building into the air inside.

The most efficient materials for transmitting the sound are glass and metal; curtain-wall buildings, where the outer skin is composed entirely of glass attached to a steel frame, are particularly vulnerable. Passive vibration dampers can be attached to the buildings but, as with the double glazing, this is not a perfect solution.