The sub-great bass recorder, also known as contra great bass and contrabass, is a recorder with the range C–d1 (g1). It is manufactured in both bent ("knick") and square designs. The design with a square or rectangular cross-sections 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. Through this special and proprietary design, the instrument can be played with a very short bocal.
The American recorder player Michael Barker has combined a Paetzold contrabass recorder with two computer-controlled synthesizers to create what he calls a "midified blockflute".
The sub-great bass recorder was developed by Herbert Paetzold in Ebenhofen. Today, this recorder size is produced and distributed by the workshop Kunath under the brand name "Paetzold by Kunath".