bells have increased significantly. It was one of the most important instruments in Baroque polychoral works, along with the cornett and organ. Instrument sizes Sackbuts come in several sizes. According to Michael Praetorius, these were: The pitch of the trombones has (notionally) moved up a semi-tone since the 17th century, and this is explained in the section on pitch. Because the tenor instrument is described as "Gemeine" (common or ordinary), this is probably the most widely used trombone. The basses, due to their longer slides, have a hinged handle on the slide stay, which is used to reach the long positions. A giant contrabass sackbut known as the () was known in 16th and early 17th centuries, and is represented by only a few existing instruments. One surviving original instrument in B♭, an octave below the tenor, built in 1639 by Georg Nicolaus Öller in Stockholm, is housed in the Scenkonstmuseet. In addition, Ewald Meinl has made a modern copy of this instrument, and it is currently owned and played by Wim Becu. Construction The bore size of renaissance/baroque trombones is approximately and the bell rarely more than in diameter. This compares with modern tenor trombones, which commonly have bores to and bells to . Modern reproductions of sackbuts sacrifice some authenticity to harness manufacturing techniques and inventions that make them more comfortable for modern players, while retaining much of the original character of the old instruments. Some original instruments could be disassembled into the constituent straight tubes, bowed tubes, bell flare, and stays, with ferrules at the joints. Mersenne has a diagram. (Little imagination is needed to see how it could be reassembled—with an extra tube—into something approaching a natural trumpet.) There is a debate as to whether they used tight fittings, wax or another joining substance. Modern sackbut reproductions are usually soldered together. Some modern sackbut reproductions use glue as a compromise to give a loose fitting for high resonance without risk of falling apart. Tuning slides came in during the very late 18th century. Early trombonists adjusted pitch with the slide, and by adding variously shaped and sized crooks. Modern reproductions often have a bell bow tuning slide or telescopic slide between the slide and bell sections. Crooks are still used, as are variously sized bell bow sections for larger changes. The stays on period sackbuts are flat. While the bell stay remained flat, from about 1660