Spruce has characteristics that make it ideal for the "top" of an acoustic guitar (the part with the sound hole and bridge). Spruce is a straight-grained wood, and is very strong for its weight. In fact, Spruce was the wood used in early 1900s aircraft because it was very strong, yet still very light. For a guitar, this means a thin sheet of Spruce can be strong, yet easily transmit the resonance of the strings. It's this top-wood resonance that contributes the most to the sound character of a guitar. Three types of Spruce are used for Voyage-Air guitars: Select Spruce, Solid Spruce, and Sitka Spruce. All three make for a great-sounding instrument, and all have various considerations in terms of price, durability and performance.
Select Spruce is an engineered, high-technology laminate that uses thin layers of Spruce, bonded under heat and pressure. Because of the lamination process, Select Spruce is more flexible than a solid, single layer of Spruce. It is also more temperature resistant, and it holds up better to the occasional 'dings' and 'bangs' that occur when traveling with a guitar. For a travel guitar, Select Spruce is strong, inexpensive, durable and sounds really good. Select Spruce is used in the Voyage-Air Transit series guitars.
X- Bracing: Consists of two braces forming an X shape across the soundboard below the top of the sound hole. The lower arms of the X straddle and support the ends of the bridge. Under the bridge is a hardwood bridge plate which prevents the ball end of the strings from damaging the underside of the soundboard. Below the bridge patch are one or more tone bars which support the bottom of the soundboard. These abut one of the X braces and usually slant down towards the bottom edge of the soundboard. The top tone bar butts against a portion of the bridge patch in most instruments. Above the sound hole a large transverse brace spans the width of the upper bout of the soundboard. Around the lower bout, small finger braces support the area between the X-braces and the edge of the soundboard.
Back Binding: Acoustic guitars have the edges bound to create stronger joints between the top, sides, and back of the guitar. The binding acts almost as a brace around the outside of the guitar. It protects the fragile, grain edges of the top and back while helping attach them to the sides. Binding is important structurally and aesthetically.