Slogan: sound technology

Wave Field Synthesis Project at the TU Berlin

At the Technical University of Berlin, a lecture room was equipped with 110 of our 8-channel WFS-modules, to create a virtual sound environment by Wave Field Synthesis with a line of loudspeakers surrounding the audience.
On the surrounding length of 86 m, 832 audio channels are provided. The 832-channel audio for the lecture room is processed on 16 WFS-PCs, each one provided with a 64-channel MADI-interface, connecting to local MADI-to-ADAT converters over coaxial cable. An 8-channel ADAT interface embedded in each HD2-module receives the 24-bit audio data via optical fibre.

The picture shows the uncovered modules during the installation.
For wave field synthesis, the listener has to be surrounded by a line of speakers, as closely-packed and small as possible. A module was designed with 8 broadband channels, spaced in intervals of 10 cm and 2 woofers in 40 cm. The broadband channels consist of 3 speakers controlled by a passive crossover network to have a broad horizontal and a narrow vertical directivity.
Inside the module, 10 power amps (8×40W, 2×100W) and a HD2 DSP module are working to provide FIR crossovers and peak- and RMS-limiters. With this, a linear phase of the whole system and an optimum efficiency can be achieved.
The modules provide an Ethernet interface to be controlled remotely and an ADAT input.

WFS module from Four Audio

Summary of module specs

  • ADAT interface
  • 10 power amplifiers (8×40W, 2×100W)
  • contains HD2 loudspeaker management system for loudspeaker equalization and protection

The included HD2 loudspeaker management system provides

  • precision limiters in each channel (peak and RMS for the power amp, peak and temp. for the loudspeakers)
  • amplitude and phase equalization with FIR filters for overall linear phase response
  • additional IIR filters for room equalization
  • remote control via Ethernet, DHCP
  • for more details, see this page

The dimensions of the module are 80 × 60 cm

Publications on this Subject

Goertz, Makarski, Moldrzyk, Weinzierl, Zur Entzerrung von Lautsprechersignalen für die Wellenfeldsynthese, Tonmeistertagung 2008, Leipzig (in german)

Makarski, Goertz, Weinzierl, Moldrzyk, Zur Entwicklung von Lautsprechern für die Wellenfeldsynthese, Tonmeistertagung 2008, Leipzig (in german)

External links

WFS Page at the TU Berlin