Tomba sonora is a site-specific musical project for the mausoleum in the Emanuel Vigeland Museum in Oslo. The mausoleum is in effect one huge tomb, and it's reverberation time has played a key role in how this music has been conceived and composed by Kristin Bolstad; moreover, the room's special frequency response and the overtones derived from it are also used actively in the musical material. The positioning of the vocalists and the direction of the sound are among the many ways the acoustic qualities of the room's space are used creatively to shape the flow and movement of the music. To gain entry to the mausoleum one has to bend down low to get through a low, narrow opening. Just above this doorway is the urn which contains Vigeland's ashes, so this is an act of obeisance that has to be made by everyone entering the mausoleum. The mausoleum houses not only this urn but also Vita, his magnum opus, a work that consists of frescoes that cover the walls of the 800-square-metre room, which took him most of his life to complete. Vita depicts human life from conception to death, with hundreds of nude figures which, in scenes of intense intimacy, reflect both a Darwinian and a Christian perception of life. The acoustics of this mausoleum are a significant part of the multisensory immersive experience any visitor will encounter. The hard surfaces of the stone walls reflect the sound from all directions and one feels enveloped by it. Performers' interaction is also strongly affected by this reverberation, something musical phrasing has to take into account. The long reverberation calls for slower tempi, reduced dynamics, gentler articulation, and, not least, very patient listening. Perceived reverberance is measured by an acoustic parameter, and in a typical concert hall it would be 1-3 seconds. In the mausoleum of Vigeland the EDT parameter measures 13 seconds. The room insists that everything happens slowly. The music creates a room that is quieter than a room without sound, and we can only find our way to this quiet room by slowing down and giving time.