Futuristic system pumps all around sound

By RICHARD WOOD

If you have $34,000 burning a hole in your pocket and you are hankering for the latest in loud-speaker technology, then Bang & Olufsen's weird-looking Beolab 5 speakers could be just what you need.

The speakers, which seem a bit like the Daleks in Dr Who, were demonstrated in Sydney this week, and will be available here in spring.

They use what is called "elliptical sound lens" technology, apparently the biggest change in loud-speaker technology for decades.

The treble and mid-range speaker drivers point upwards into curved elliptical reflectors that focus the sound waves through a 180 degree horizontal arc in front of the speaker.

The point here, says Poul Praestgaard, Bang & Olufsen's acoustic technology manager, is that the speakers act like a ship's lantern, rather than providing the torch beam of normal speakers.

This means the same sound can be experienced no matter where you are in the room, and sound reflection off ceiling and floor is reduced.

Standing 97cm high and weighing 61kg, the speakers deliver 2500 watts each.

Volume is adjusted by remote control. The bass drivers are housed in a black, upside-down cone.

Cylindrical brushed aluminium layers, which provide a futuristic look, separate the sound lens outputs to prevent interference. The 38cm and 16.5cm pair are each driven by built-in 1000 watt digital amplifiers.

Another technology in the speakers is adaptive bass control, using a moving microphone. This customises the sound to a particular room.

Praestgaard demonstrated this by putting a speaker in a corner and showing how this would typically cause a booming sound because of reflected "phantom" speakers.

Generally, walls all around a room act as mirrors and create interference in the sound, he explained.

At the push of a button on top, the speaker spends two minutes reading the room - analysing the acoustic responsiveness between 20Hz and 300Hz - and sets up an internal sound filter to fit.

During the process, a microphone at the base moves a few centimetres in and out.

Afterwards the speaker, despite its location, performed as well as a reference speaker sitting a couple of metres into the room.

The Beolab 5 is the first digital speaker from Bang & Olufsen, using a 32-bit digital signal processor to process the sound before amplification.

The processor implements the adaptive bass control system, handles volume control and is used to calibrate the speakers so that they are all the same.

Bang & Olufsen said the acoustic lens technology would eventually find its way into smaller speaker systems.

Let's hope these might also have a smaller price tag, so that the wider public can also enjoy what appears to be a significant breakthrough in sound engineering.

* Richard Wood travelled to Sydney as a guest of Bang & Olufsen.