Sub-contrabass recorder

The sub-contrabass recorder is a member of the recorder family with a low note of FF (or F₁ in SPN).^{[citation needed]} It is manufactured in a design with a square or rectangular cross-section, which was first patented in 1975 by Joachim and Herbert Paetzold. They are made from plywood and have a doubled-back bore like a bassoon, which reduces the exterior length of the instrument. They also have wooden keys.^[1] Through this special and proprietary design, the instrument can be played with a very short bocal.