A second "for the record" on readymade's resonance and volume. I have an hourglass shaped McSpadden, walnut with a redwood top, and when I crank it up it drowns out my husband's 1919 Gibson A2 mandolin, and can hold it's own with his sister's fiddle, which is louder than your average rock concert. Needless to say, I don't normally play it at that volume, but I do have to watch it in group situations or I can't hear what other folks are up to. I also have Folkroots deep bodied baritone, again with a redwood top, and it can speak with authority as well.

Both these instruments have hollow fretboards, unlike my "cheap and cheerful" plywood starter dulcimer, which is indeed a 2 x 4 with a soundbox: no resonance and dreadful intonation (what did I know when I bought it).

Unlike guitars, good dulcimers are not horrifically expensive. In fact, I had a opportunity to ear test my McSpadden against some of Dwain Wilder's instruments. His are incredible works of art, but mine held its own...I couldn't quite see spending five+ times the price of a McSpadden, despite the charms of having an instrument built just for me.

The trick is to find a dealer who has a variety of instruments and play them all until you find the one that speaks to you. (I recently did that for a guitar, which is why I spent ~$800 for a Martin 000-15s instead of ~$1,300 for the fancier 000-17s. You gotta shop with your ears.