A smartphone having two microphones is used for determining the direction of a loudspeaker in a surround system setup. This is performed using smartphone rotation in azimuth and polar angle direction while capturing in its microphones a test signal from a current one of the loudspeakers. From the microphone signals a corresponding TDOA value is calculated, and the smartphone is rotated until that TDOA value is nearly zero, resulting in a loudspeaker direction information.