Audio Perception Laboratory

The Advanced Audio Systems Group is equipped with a variety of listening facilities for performing subjective tests or for conducting research activities in audio perception. The Audio Perception Lab is a controlled environment for performing sensitive listening tests. It is among a handful of such listening rooms in the world and the sole on in North America. A second facility, the Psychoacoustics Lab, is used for research and hearing tests.

Audio Perception Laboratory

The Audio Perception Lab includes two separate listening rooms which provide a controlled environment for performing sensitive listening tests. Structurally separated from the building in which they reside, both listening rooms have a background noise rating below NR10. Their acoustical properties can be varied to accommodate various desired listening conditions. In their typical configuration, the rooms' acoustics conform to ITU-R specifications described in Recommendation BS-1116.

The two listening rooms are adjacent to a control room equipped with a variety of professional digital audio equipment including Apogee DA8000 and Prism DA-1 AD/DA converters and the Mackie D8B digital mixer. Recordings can be done on hard disk via Digital Audio Labs CardDOC or Sonorus StudIO digital audio cards or onto DAT. Multichannel digital recordings can be done either onto Tascam DA-88 & DA-38 tape recorders or onto hard disks via the Sonorus StudIO card. We are also equipped with a variety of Bruel&Kjaer and Audio Technica microphones.

Psychoacoustics Laboratory

The psychoacoustics lab is equipped with an audiometric chamber that enables precise measurement of the perception of low level audio signals and the discrimination of small differences between them. Audio is computer-generated and presented to the listener via a Digital Audio Labs CardD digital sound card and an external Spectral Synthesis Model 2218D/A converter, and then to Stax SRM-1 headphones located in the audiometric chamber. The listener interacts with a computer screen through a window in the chamber using a mouse control.

Software to control listening tests and experiments was developed in-house. These include software to measure the hearing threshold and the just noticeable differences in frequency, as well as software to conduct signal detection experiments for measuring the masked thresholds of signals in any audio context.

Transmission Signal Processing Facilities

Our research activities in the area of digital communication systems lead us to conduct simulation and real-time testing of our algorithms before making them available to customers. For that purpose, we resort to a variety of powerful state-of-the-art multicore workstations.

The wireless transmission technologies we develop are first assessed by computer simulations in non real-time mode using Matlab as our primary test platform. Once a proof-of-concept has been established, they can be implemented in real time Software Defined Radio (SDR) products which are commercially available through licensing agreement.

The real time software is developed in C/C++ and our development platform is the PC running under Windows XP. We can also port our SDR code to other platforms (such as the Blackfin DSP) and operating systems as needed by the specific customer requirements