Radiused vs. Non-radiused
In the world of string instrument fingerboards, there are two basic types: radiused and non-radiused. Radius in this instance refers to the arch of the top of the fingerboard. Bowed instruments have rather severe radii so that each string can be individually bowed without the bow touching adjacent strings. Guitars aren't usually bowed, so the radius of guitar fingerboards isn't as extreme as those in the violin family. Violins can have something like a 1.6 inch radius, whereas most acoustic guitars average around 16 to 20 inches. Electric guitars are around seven inches. And there's the matter of compound radii, but that's another topic for another blog post. Classical guitars are an entirely other matter. Classical guitars have a non-radiused, or flat, fingerboard. There are various reasons for this. Classical guitar fingerboards are flat to facilitate precise finger placement and easier access to strings for complex fingerstyle (in the right hand) playing.
