The Origins of the Acoustic Guitar
Changes to the acoustic guitar
Acoustic guitars were initially very similar to classical guitars
The guitar shown in the photo is a "dynamic guitar" sold by Yamaha roughly 50 years ago. This was before the acoustic guitar really came into being, and is basically a classical guitar strung with steel strings. Although classical guitars long ago used catgut strings made from sheep intestines before switching to nylon strings, this guitar instead used steel strings. The strings were wound using a pegbox-just like a classical guitar.
Dynamic guitars were known for producing bigger sound since they used steel strings instead of nylon strings. The shape and thickness of the body was subsequently modified to produce an even bigger sound-one more step closer to perfecting the acoustic guitar.
Guitar bodies are getting thicker
Take a look at the two guitar bodies in the photo. The guitar on the right is the first acoustic guitar built in Japan (1966), while the one on the left is a modern instrument. The older guitar is thinner, while the newer one has a thicker body. A thinner body produces a cleaner sound, and while that is certainly not a bad thing, modern players prefer a fuller sound over a smaller instrument, and so guitars have tended to get thicker as time goes on.