Researches in the field of the room acoustic emphasize the need to harmonize the acoustic characteristics of the room and the performed music so that the musical experience of a listener matches his aesthetic comprehension of the sound. The first researches in the domain of acoustic room design were mostly based on the reverberation theory. In later researches priority was given to early reflections and afterwords to lateral energy. Proceeding from the assumption that the listener is the only criterion of the room quality, we came to the notion of “the desired” characteristics of the sound field in the room. The notion implies the qualities of the sound field that listeners consider optimal in the sense of the complete sound impression in the room. So, the theory of subjectively desired characteristics of the sound field as a specific theory in room acoustics was developed. As it is a relatively new approach, there is the possibility for numerous researches aiming at the implementation in theory and modeling the theory. That possibility is used in this book which is specially interesting for those in the field of music and audio engineering.