To improve the accuracy in terms of precision and recall of an audio information retrieval system we have created a domainspecific ontology (a collection of key concepts and their interrelationships), as well as a novel, pruning algorithm. Taking into account the shortcomings of keyword-based techniques, we have opted to employ a concept-based technique utilizing this ontology. The key problem in the retrieval of audio information is to achieve high precision and high recall. Typically, in traditional approaches, high recall is achieved at the expense of low precision, and vice versa. Through the use of a domain-specific ontology appropriate concepts can be identified during metadata generation (description of audio) or query generation, thus improving precision. In case of the association of irrelevant concepts to queries or documents there is a loss of precision. On the other hand, if relevant concepts are discarded, a loss of recall will ensue. Therefore, in conjunction with the us...