Measuring dB / max amp in Novocaine

test.mm

[audioManager setOutputBlock:^(float *data, UInt32 numFrames, UInt32 numChannels)
    {
    // Measure dB
        float maxAmp = abs(data[0]);
        for (int i=0; i < numFrames; ++i)
        {
            for (int iChannel = 0; iChannel < numChannels; ++iChannel) 
            {
                if (abs(data[i*numChannels + iChannel]) > maxAmp) {
                    maxAmp = abs(data[i*numChannels + iChannel]);
                }
            }
        }
        printf("Maximum Amp in dB: %f\n", 20 * log10f(maxAmp));
    }];