Pre-war acoustic guitars are treasured for their amazing tone. These instruments were built lightly and thinly using high modulus (stiffness-to-weight) old-growth wood such as Adirondack spruce for the tops and bracing structure. Also, very hard tropical woods for the guitar backs and sides. However, these woods and even those similar varieties are now very rare. Also, the woods in these pre-war instruments have since aged, with the natural resin in the wood becoming crystalline, further enhancing the material rigidity. There are other variables, such as the very hard hide glue, which is said to improve the vibration transfer of the strings. Regardless, since the soundboard accounts for roughly 95% of the tone of an acoustic, I attribute the better tone mostly to that assembly.
Ekoa is designed to reproduce the pre-war vintage sound. Our El Capitan is made from Ekoa-brand high-performance, eco-friendly linen fiber composite for all the stability of carbon fiber but the look, feel and sound of wood. With the El Capitan guitar, musicians get what was previously unobtainable — the experience of a premium, vintage old-growth wood instrument in a lightweight, durable and sustainable package. The naturally vibration dampening Ekoa is lower density than old growth spruce but stiffer and in two directions rather than only one.
Read more about Ekoa on the Wikipedia Ekoa Page.