Signal similarity search is an important technique for music information retrieval. A basic task is finding identical signal segments on unlabeled music-signal archives, given a short music signal fragment as a query. In such a task, the search must be fast and sufficiently robust against possible signal fluctuations due to noise and distortions. In this special session paper, we describe a search method designed to cope with additive interferring sounds by spectral partitioning. Then, we introduce another method designed to be robust under multiplicative noise or distortion based on binary area representation. © 2007 IEEE.