In the music cultures of the world we encounter both tacit and verbalized musical knowledge to various degrees. In order to reconstruct emic views on musical concepts and practices which are a prerequisite of any seriously culturally informed musical analysis we need to disclose local knowledge by appropriate means even if it is not directly open to verbal discourse. Current computer technology enables us to set up interactive experiments where local experts can verbally address relevant musical features in discussing audio examples which have been prepared by the researcher. The performance of virtual musicians can be evaluated by the local experts and various relevant parameters may be investigated individually if suitable versions of customary pieces are available. Thus aspects which seem to be tacit knowledge because they usually elude verbal discourse can be made accessible and transformed into verbalized, declarative knowledge. The paper presents preliminary results of a case study on Central Javanese gamelan music (karawitan) where renowned Javanese musicians commented on computer-generated versions of traditional compositions regarding the idiomatically appropriate performance practice of the virtual ensemble as well as the tuning and sound of various virtual gamelan sets emulated by the computer.