In a direction-finding system based on TDOA the time difference of arrival (TDOA) that occurs when two receivers are synchronous and spatially separated is measured. By correlating the received signals, an estimation of the time difference can be made. A hyperbolic function represents all possible transmitter positions for the given time difference. VM three of more receivers a single position can be estimated. Based on the TDOA-technique an audio-demonstrator has been developed and implemented. The audio demonstrator has been tested in a non-silencing room where sound from a loudspeaker has been recorded into MATLAB through the use of microphones. With an accuracy within a couple of hundreds of a degree, a direction can be estimated with simulated signals for a given SNR (usually 25dB) or a position within a few centimetres when the transmitter is a couple of meters away. Tests with real audio signals show less satisfying results. The position can at best be estimated with an accuracy of 5% of the distance to the receiver when the microphones are spread out 0.7m apart. The performance of the audio-demonstrator can be improved by using better methods for finding the points of intersection between hyperbolas and by weighting the estimated time differences.