This is the first Spring Dulcimer that was ever built, the SD1. It was built in 2005. It is the prototype. I had never built anything before so I had to commission someone to help with it. This model uses three sizes of springs for treble, mid and bass. The tuning scheme alternated between chromatic and fifths. The bass and mid springs were a fifth apart followed by the treble spring, which was also fifth apart from the mid and an octave higher than the bass. This arrangement between the treble, mid and bass was repeated chromatically giving the Spring Dulcimer twenty four notes.