Nate,
Good to be back. I fell down the rabbit hole of trying to master the use of 3D printed components to produce dulcimers with sound characteristics similar to wood. After several years of exploring a lot of dead ends, I have developed techniques that yield the acoustic and visual results I was seeking. I will be posting more details on my website, at stephenslutherie.com soon. You can also find my most recent blog post there, which discusses the smart dulcimer prototype I just completed. It incorporates a HyVibe System developed for guitars. The system is designed to give many sound shaping tools to acoustic guitars. Additionally, it gives onboard capability to record, loop, overdub up to four tracks and do a few more cool things. All of the features work well on my dulcimers since they are constructed more like guitars than traditional dulcimers.
The octaver effect tries to simulate shifting the played note a specified amount up to an octave above or below the note. In the process, there is significant loss of tone quality. If just adding a bass line it could be acceptable in some circumstances. What I am finding with most of the effects is that they can be added in small amounts to the basic sound of the dulcimer. Since you can layer two or three effects on top of one another the possibilities are endless. In fact, you have to limit your playing with the effects so that you get on with actually playing the dulcimer. Once dialed in and stored, however, the effects are easily recalled for use as appropriate. Some EQ, reverb and a touch of chorus can really warm up the sound and more than make up for any slight loss of character the 3D printed body may have caused (note that the tonal purity of the printed body can also be an asset).
I think you would enjoy the freedom a 3D printer provides to rapidly prototype ideas. They are starting to show up on craigslist for very attractive prices. In a few cases, ones that need repair are virtually being given away. Even a small printer can make instruments in sections. The software for designing and slicing the model are free downloads as well. With or without 3D printing, keep up the creative designs. They keep us all questioning what we know about the humble mountain dulcimer.