I recently started to use spectral decomp, and have several questions here:

1. When I set the low peak frequency, high peak frequency, and sub-band numbers, there is a plot below. Obviously, this plot shows the frequency ranges of each sub-band. What other information can this plot tell? My friend told me that if the red dots are not located close to the crossings of curves, that means you need to change your settings to make them match. I do not agree with it because it does not make sense.

2. What is best way to estimate the low/high peak frequency from the spectrum survey? Use amplitude 0.5 as a cut-off?

3. Theoretically, the more sub-bands you set, the narrower frequency range you will get, the more precision your results have. Meanwhile, if the frequency range is too narrow, you will start to lose the geological information. So how should I find the balance?