In analyzing the audio recording of a string instrument, I am struggling with pitch estimation. I am using the pYIN algorithm and every pitch estimation I'm obtaining is off by one octave. I assume that's caused by the fact that they're using the FFT. Looking at a spectrogram I observe that the second harmonic lasts longer and has more power. I assume that this causes the octave error.
My questions therefore are:
- Under what conditions is the second harmonic more prominent than the fundamental?
- How can this effect be mitigated in the context of pitch estimation?