Round-backed guitars are typically made of wood, and the back of the guitar is usually made from a single piece of wood. The back of the guitar is then attached to the sides and top of the guitar using glue and/or nails.
The shape of the back of a guitar can have a significant impact on the sound of the instrument. Round-backed guitars tend to have a warmer and more mellow sound than flat-backed guitars. This is because the rounded back of the guitar allows the sound waves to resonate more freely.
Round-backed guitars are often preferred by players who are looking for a mellow and warm sound. They are also popular among players who play fingerstyle guitar, as the rounded back of the guitar allows for a more comfortable playing position.
Some popular examples of round-backed guitars include the Martin D-28, the Gibson J-45, and the Fender Telecaster Thinline.