The male vocal quartet Svetoglas was founded in 2009. Daniel Spassov, Stanimir Ivanov, Viktor Tomanov and Milen Ivanov interpret ancient Bulgarian music - both folklore and Orthodox chants. Their art is well known in Norway, Spain, Russia, France, Great Britain, Belgium, Italy, Colombia and many other countries. In the music album The Nightingale's Song Svetoglas release their imagination to create a specific and unusual interpretation of the Bulgarian folk music tradition. It is both bright, holy and intimate; it is also global because it carries with the young and living voices the spirit of the native and old-aged in the modern global spaces. The Svetoglas performers offer their listeners a musical journey to the song folklore, taking them to different regions of Bulgaria - Midwest and Northwest Bulgaria, Pirin Macedonia, Thracia, Strandzha. In an original way, the singers go beyond the boundaries of these geographic orientations and reach an overall Bulgarian musical sound. Their performances are contemporary but they also resonate with the musical past of Bulgarian people. In their vocal interpretations, they keep alive the spirit of Bulgarian traditional music of the pre-modern past, infusing it into new musical forms. They create magnificent vocal miniatures by hybridizing different components of the folk songs included in the album. The album The Nightingale's Song sounds beautifully as it combines high aesthetic criteria with an intimate experience; a respect for the tradition and a daring search for new pulsations. The singers of Svetoglas expand their vocal and interpretive skills in their new experimental musical album by developing hybrid and alternative forms in presenting and renewing the traditional Bulgarian folk singing. These vocal hybrids are organized in specific ways as complex structures of interpenetration of the singing voices that are symbolic of the soul's affects. The songs featured in the music album reveal how musical sounds from the past can be inspiring for contemporary artists and audiences. Through the songs of Svetoglas, the soul listens to itself in the harmony of it's parts, which is of the utmost importance for unlocking the sound harmonies in us. Thus in sharing the sounds of Svetoglas - human and Bulgarian, beautiful and fascinating, they help us preserve in ourselves the harmonic structure of the soul, the archaic sense of Bulgarian times and discover new worlds and music horizons.