Processor-implemented methods and systems for polyphonic note detection are disclosed. The method includes converting a portion of a polyphonic audio signal from a time domain to a frequency domain. The method includes detecting a fundamental frequency peak in the frequency domain. The method then detects a defined number of integer-interval harmonic partials. If a defined number of integer-interval harmonic partials relative to the fundamental frequency peak are detected the fundamental frequency is recorded as a detected note. This process is repeated for each fundamental frequency until each note in the polyphonic audio signal has been detected. For example, this method allows detection of each note in a strummed guitar chord to provide feedback on the tuning of each string in a strummed chord or allows detection and feedback of the timing and pitch errors for guitar chords played along with a reference track.