Among the works classified by Umberto Eco as open, a special place is taken by the artistic works representing the way of existence connected with the category of the openness of the second degree, reserved for physically closed works. Such works were definedby the Italian semiotician as sources of transmissions of ambiguous structure. In the article, attempts were made to determine the characteristics of such works on the basis of the propositions from Eco’s Open Work, taking into account the existence of the perceptual work-recipient relationship determined by the structural properties of the artistic transmission. Thereby, it became possible to determine what factors foster the unambiguity of the musical message and, by means of contrast, the description of circumstances leading to its increased ambiguity.