I got to mess around a bit more today and it wasn't that tough to recreate the boxy sound. Sure enough, Studiodawg, right in the 450hz range. Strangely, even when I dropped that area -12dB, I could still get it to do it with an extra hard pluck in the sonic range I described before. Changing my plucking a bit cleaned it up but not sure I want to have to remember the 4 notes I have to pluck differently![]()
How did you "drop that area" by -12dB?
The only way I know of to tame undesired sound colorations is by using a decent full parametertric multi-band EQ. Creating a steep notch up-curve and sweep the frequency until the "boxy" is up in the face. Then inverse the curve for being a down-notch, play with Q-factor and with the damping. Eventually you have to do this in the harmonics with another EQ-band.
Doing so I can get rid of every troubeling coloration or feedback, even with extreme room acoustics. Only drawback - its taking a lot of time and experience.
A word to the Fishman Platinum: I have had this device and ditched it soon. It simply deathened my sound and its EQ bands never helped. I always messed around with it to get a good sound. Only when I bypassed it I realized what the big troublemaker in my chain has been - the Fishman...