This paper describes the system developed at I.I.T. Bombay for Query-by-Example Search on Speech Task (QUESST) within the MediaEval 2015 evaluation framework. Our system preprocesses the data to remove noise and performs subsequence DTW on posterior/bottleneck features obtained using four phone recognition systems to detect the queries. Scores from each of these subsystems are fused to get the single score per query-utterance pair which is then calibrated with respect to the cross entropy evaluation metric.