Acoustic guitars are fussy. Without proper babying, they can warp or crack, and fluctuations in humidity cause the guitar to go deeply out of tune. But we keep making them out of wood because nothing sings as prettily as old trees. Blackbird’s El Capitan has the warm sound and timeless looks of wood, minus the fragility. The six-string is crafted from Ekoa, a composite made of flax and industrial waste bioresin. It’s lighter than carbon fiber and has a higher stiffness-to-weight ratio than old-growth Sitka Spruce, the preferred material for high-end soundboards. Bonus: It doesn’t warp. “We like to say it’s old-growth wood without the worry,” company founder Joe Luttwak says. To build the guitars in Blackbird’s San Francisco factory, Luttwak and his team lay more than 100 tiny pieces of Ekoa onto an aluminum mold, then cure it under heat and pressure for two hours. The resulting unibody El Capitan is 30 percent lighter than the average acoustic guitar and has a hollow neck that adds even more resonance. It’s a lovely instrument with an earthy tone that you don’t have to handle with kid gloves—just don’t go all Pete Townshend with it. $3,195 & up