Many students are interested in the periods of their spectral peaks. Plotting against frequency is common, but it may be nice to add one of several suggestions below:
add an option to plot against period in stead of frequency (most people would be agains this, however)
add an option for a secondary x-axis above, with the period info. This would be a non-linear axis though
when you click any of the points/peaks in a spectrum, show the period in addition to the x- and y-values
Many students are interested in the periods of their spectral peaks. Plotting against frequency is common, but it may be nice to add one of several suggestions below: