57. The server of claim 56 , wherein the database updating unit is further configured to store the input sound model in the server database if the similarity between the input sound model and the first sound model is less than the similarity threshold.
56. The server of claim 53 , wherein if the confidence level of the second label is less than the second confidence threshold: the communication unit provides the client device with an indication of a failure in recognizing the input environmental sound; the sound recognition unit identifies a set of the one or more sound models with information corresponding to at least one of a first location and a first time that match the at least one of the location information and the time information and identifies a first sound model having a greatest similarity to the input sound model from the set; and a database updating unit merges the input sound model and the first sound model in the server database if the similarity between the input sound model and the first sound model is greater than or equal to a similarity threshold.