First of all, thanks for all the effort to research and model this!
A friend of mine did some modeling as well, and came to the conclusion that there should be a treble increase, rather than the perceived decrease:
Even though the exact values differ from your (probably more correct) model, the effect is clear.
So, what could we really conclude from all this? That our models are too simplistic? It seems like they contradict your empirical tests? One indication of the complexity is the fact that in your real recording example, the 12th and 13th component is really louder in the rolled-off case, right?
Congrats! That's a nice guitar. In the future, just go out and play them. If you want to know the difference between two of these track them down at a guitar shop and play them. Nothing is better than your own hear.
Thanks for the info! My little brother is learning acoustic guitar. Until now, he has learned different techniques like strummer, flatpicking or travis picking. His music lesson is going well under the trained professional and hope so he learns well and play beautifully!
@Hudson_Dean Hey man! Great question! I think I can add something to this thread. I really love that Fingerstyle Guitar always is changing, and I discover new ways of playing all the time! If you look at the "Boom Chick" Chet Atkins Style, there's many players playing in this style - but there are some significant differences between say Merle Travis and Chets playing! Chet played the bass notes very articulated and usually have the same picking pattern for the right hand thumb. For instance, if he'd play a regular C chord in the open position, he'd play the A string first, then the D string, then the E string, and back to the D string. That's in 4/4. Merle on the other hand would kind of "strum" and strike several bass-notes at the same time using the thumb pick. Starting on the A string, and then kind of strum the D, G and even the B string at once, and then play the low E string and then strum those 3 strings again! Similar to Chet but still way different! There are so many things that I could add to this topic but for now I'll let someone else take over, and I'll be back!! Looking forward to reading more from you Hudson! Kind regards/Emil