That sounds almost like a “psychological” radius. You know it’s there, even though you can’t feel it or see it at all without some precision measuring tools. But the knowledge of its existence may give you some extra confidence or mental confort in difficult acrobatic positions. Maybe.Beowulf wrote: ↑Tue Jan 15, 2019 9:23 pmI asked the technical service manager at Yamaha Canada about the 3000mm radius and here is the response:
""The 3000mm radius is correct; it’s almost completely flat. Traditionally, classical guitars are completely flat; but that ever-so-slight radius adds to the playing comfort."
However, I have a vague memory of reading somewhere that fingerboards can sometimes, after years, develp a slight concavity due to shrinkage of the wood or whatever, and therefore building them with a very slight convexity may act as a preventive countermeasure against this development.