Merlin Spruce SG Dulcimer Guitar Natural. Inspired by the dulcimer, the Seagull Merlin is a portable 4-string diatonic acoustic instrument thats just simply fun to play and hard to put down. The Seagull Merlin Natural Spruce SG features a solid spruce top with a mustache style Tusq bridge, compensated saddle, 3-piece rock maple body with drive-through neck design and tune-up with vintage style open-geared tuners.