Project Red: The Sound Projector

This is the homepage of the red project group in the course 2E1367, a project course given at KTH (The Royal Institute of Technology) . Our group consists of six gifted students and the project is to create our own digital sound projector using four loudspeakers. 

Background

With the development of consumer electronics and digital audio, home cinemas have become popular and affordable. However, some users are put off by the idea of having to install a real 5-channel plus subwoofer sound system at home. The main reason is all the hassles with placing the speakers in one room and connecting them with heavy, unaesthetic wires. Would it be possible to obtain the same effect with only one box placed on the front?
Digital sound projectors are one of the most dynamic state-of-the-art solutions. The projectors utilize an array of many microdrives to form a number of virtual speakers that mimic multichannel sound. The secret of these virtual speakers is beamforming with several techniques: different angle-of-arrival, phase, power and delays. By producing tight, focussable beams of sound, the digital sound projector projects the separate sound channels around the listener's room. Then, the reflection of these beams on the walls and other surfaces in the room will finally come to the listener from left and right, front and rear.

Commercial implementations of this idea have been on the market for several years now, being Yamaha and Pioneer two of the most successful manufacturers. They usually have a large number of speakers (>50) set in two dimensions, and can be found for as little as 4 000 SEK for the very basic models. That's considerably less that the 280 000 SEK the Pioneer PDSP-1 Digital Sound Projector cost when it first came out with its 254 individual speakers.

Specification

The goal of this project is to design and implement a simple digital sound projector by using a very limited number of small speakers and a DSP card. The surround channels should be calibrated by microphones to provide satisfactory experience in real-world listening tests.

This many coffee packages have been used: