**1. Introduction**

Recently surround-sound systems have become popular. The effect of "surrounding" the listener in sound is achieved by employing acoustic phenomena which influence localizing the source of the sound. Similarly to stereophony system the time, volume and phase interrelations in signals coming from each sound source are taken into account. Additionally the influence of the acoustic system created by the pinna, head and torso on the frequency characteristic of the sound is taken into consideration. This influence is described by the Head-Related Transfer Function (HRTF). The knowledge of the human physical body characteristics' influence on the perception of the sound source location in space is being more and more frequently applied to building sound systems.

So far the best method of including the influence of the human body on the frequency characteristic of the sound is the HRTF measurement for different locations of the sound in relation to the listener. Then the achieved measurement results are used for creating a database meant for the sound reproduction. Creating a proper HRTF database is a difficult problem – every human exhibits individual body characteristics therefore it is not possible to create one universal database for all the listeners. For this reason applying the knowledge of the human body influence on the frequency characteristic of the sound is impeded. In order to include these parameters it is necessary to conduct all these laborious measurements for each individual.
