An automatic content recognition system that includes a user device for the purpose of capturing audio and generating an audio signature. The user device may be a smartphone or tablet. The system is also capable of determining sound level at a user device and refraining from audio monitoring and/or generating audio signatures when the sound level is below a threshold. Sound level may also be used to reduce the frequency of audio monitoring and/or signature generation. The system may have a database within the user device or the user device may communicate with a server having a database that contains reference audio signatures.