17. A method for recognizing an input environmental sound at a server, the method comprising: if a confidence level determined by a client device and associated with a first label associated with an input environmental sound received at the client device is less than a first confidence threshold: accessing a server database including a plurality of sound models representing environmental sounds and a plurality of labels, wherein each of the plurality of labels identifies at least one of the plurality of sound models; receiving, from the client device, an input sound model representing the input environmental sound; determining similarity values between the input sound model and the plurality of sound models to identify one or more sound models of the plurality of sound models that are similar to the input sound model; selecting a second label from one or more labels, of the plurality of labels, associated with the one or more sound models; associating the second label with the input environmental sound based on a confidence level of the second label; and sending the second label or an indication of a failure in recognizing the input environmental sound to the client device based on the confidence level of the second label.
31. The method of claim 17 , wherein a first sound model having a greatest similarity value to the input sound model is identified among the one or more sound models associated with the second label, and wherein the confidence level of the second label is determined based on a similarity between the first sound model and an associated anti-model.