Q. What is the difference between the short (640mm) and long (670mm) scale lengths?

 

A. The longer scale (standard oval hole model) creates slightly more string tension for a given guage, and possibly a bit more volume and projection. There may be some tonal effect, but it would be very subtle. The real basis for this choice would be personal preference. You may like the feel of the longer scale, or if you have smaller hands, the short scale is a good choice.