FFT frequency question Sorry if this is a stupid question but so far i have learned that after getting the results of a FFT (an array of complex numbers) you can get the frequency of a sound sample via the following:

1) Calculate the peak for each complex number: $\sqrt{\mathrm{real}^2 + \mathrm{imag}^2}$

2) Get the index of the array element with the highest peak.

3) Index $\times$ mhz of the sample audio $/$ number of elements in the array

This seems to work however I'm wondering if the second-highest peak would be the second "most present" frequency, and so on. So for example, if I had a guitar chord, and I got the top 6 frequencies, would those be the notes of a 6 stringed chord?
Unlikely.  The top 6 FFT magnitudes would more probably contain several overtones or harmonics that are stronger than the 6 note pitches in a chord.  Furthermore, some of the spectral frequency peaks can be between FFT bins, depending on the length of the FFT.  So the frequency you've calculated by just multiplying by a bin index could be different from any pitch frequency in the audio.  Depending on any window used, you might also find windowing artifacts in the FFT magnitude spectrum.