Getting the frequency from each band using ofSoundGetSpectrum

beginners
1

Hi all, I’m trying to get the frequency from each band using ofSoundGetSpectrum.

Looking at the SoundPlayerFFTExample I’ve copied this

void ofApp::setup(){
    soundPlayer.load("dig.mp3");
    nBandsToGet = 128;
    fftSmoothed = new float[8192];
    for (int i = 0; i < 8192; i++){
        fftSmoothed[i] = 0;
    }
    soundPlayer.play();
}

void ofApp::update(){
    ofSoundUpdate();
    float * val = ofSoundGetSpectrum(nBandsToGet);
    for (int i = 0;i < nBandsToGet; i++){
        // let the smoothed value sink to zero:
        fftSmoothed[i] *= 0.96f;
        // take the max, either the smoothed or the incoming:
        if (fftSmoothed[i] < val[i]) fftSmoothed[i] = val[i];
    }
}

In the tutorial written by @admsyn it is written that to obtain the frequency of a band i should use this formula

frequency = (binIndex * sampleRate) / totalSampleCount

My question are:

  1. which is the sampleRate? can I assume that it is 44100?
  2. How should i calculate the totalSampleCount value?

I do not want to use, for now, ofMaxim, ofxFFT or ofxFft (at the moment), any suggestion is welcome.

2

@admsyn maybe you have some tips?