This paper proposes TimbreStellar, an exploratory timbre retrieval system visualizing timbres as a hierarchical network. The system combines acoustic features extracted from a music representation model and ADSR-based envelope features, projects timbres into a low-dimensional space, and connects acoustically similar sounds as network nodes. We conducted a comparative user experiment with 18 participants comparing TimbreStellar with a conventional hierarchical directory interface. The results suggested that TimbreStellar encouraged more transitions across top-level timbre categories and supported users in comparing acoustically related timbres beyond predefined instrument labels.
