Pure frequency-based audio fingerprint systems have the capacity of handling very short fingerprints while being highly robust to perturbations such as additive noise or compression. However, these approaches are often complex and fail to identify time stretched signals. We propose in this paper two extensions of an existing system and test the robustness of the overall system in different conditions. It is shown that the search strategy adopted allows for a clear reduction of complexity with very limited degradation of performances and that the new system is robust to additive noise and speed changes up to 5%.