audio - Detect sound level in a certain frequency range in iOS SDK -


i working on ios app , need detect sound level frequency range. here is tutorial detecting sound level, how in specific frequency range in ios sdk?

you need capture audio microphone (avaudioengine api doing that), calculate fourier transform (the accelerate framework blazing speed) , examine amplitude of frequency bucket corresponding frequency. if it's large you've got match.

a possibly simpler , more efficient technique goertzal filter @ detecting given frequency.


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