A letter from luthier J.C Hoffmann to  Johann Friedrich Armand von Uffenbach in 1740 gives a clue...
This instrument is "my take" on the perfect lute for Bach, Weiss and later style lute music. To give my client the best possible balance over the whole register I needed a broad and not too deep body. I found interesting historical proof for my idéas in reading a letter from april 10. 1740. J.C. Hoffmann offers his beneficator to rebuild old italian lutes for 13course  use. To artfully express the musical style of the day!  The corpus consist of 15 yew ribs and is based on the famous Tieffenbrucker no 144 in Museo Bardini, Florence. (The original has more ribs).