I’m working on prototypes of two new 5-course baroque guitar models at the moment, both using the same body shape/size (my own design, based on averaging several surviving 17th century 5-course guitars) and string length (660mm), but with a few key differences:
The first will be my attempt to reproduce a good, but inexpensive players guitar of the 17th century. The surviving 17th century guitars are mostly elaborately decorated instruments which probably represent the most expensive guitars of the time, made for aristocrats or royal courts. My guess is that 90%+ of the guitars made in the 17th century would have been simpler. There are various 17th century paintings showing relatively simple guitars, which often seem to be made with locally available European woods, and without a lot of ornamentation. I’m taking the basic form of the instrument from surviving museum guitars, and the wood choices and details from paintings.
The second will be a semi-modernised version, with fixed frets, a bridge with a removable/adjustable saddle, and geared peg tuners. The aim of this version is to make a 5-course guitar which works in a modern musical context: i.e. it plays “in tune” in modern equal temperament, and is quick and easy to tune accurately, so it can be used more straight-forwardly with other modern instruments. It should also be an easier transition for someone who’s used to a modern guitar.