Can I analyze a “source” (like my favorite CD) and also my “destination” (my latest mix) and then “morph”? Or is the “source” always the same, something that provides for the best end result?
That depends upon what you consider as morphing. What Har-Bal does is analyze and display the average spectrum energy of the entire track. You can overlay the average spectrum of a reference track on the same graph (your favorite CD) as the source you wish to Harmonically Balance (my latest mix).
Then you can adjust your average spectrum to match the reference and Har-Bal will create the filter to do just that (that is you don’t design the EQ filter directly, rather indirectly). Now if this is what you mean by morphing then Har-Bal does this.
Please note though, making a carbon copy spectrum of one track using another will usually give less than impressive results and for good reason.
To give a simple explanation, matching the spectrum exactly does not work because each track will have energy concentrated in different areas (i.e.. because they are playing different notes, they may be using different instruments, they may have unique colorations due to room acoustics etc). By doing an exact carbon copy there is a high likelihood that you’ll just be amplifying the background noise.