Voice recording spectrogram

Question

I am creating a voice recording app wherein I have displayed a decibel meter. However, I would like to include a voice spectrogram on the lines of what is found in Dragon Dictate or Google Search applications.

Any suggestions on where I can start in this regard. I am a complete dummy when it comes to FFT or spectrogram analysis.

Look forward to any suggestions.

Answer 1

Apple's aurioTouch sample app (in the iOS Dev Center at developer.apple.com) includes example source code for doing an FFT and displaying a spectrogram from microphone input. Even better is using the much faster FFT in the newer iOS Accelerate framework.