Sackbut - Construction

Construction

The bore size of renaissance/baroque trombones is approximately 10 mm (0.39 in) and the bell rarely more than 10.5 cm (4.1 in) in diameter. This compares with modern tenor trombones, which commonly have bores 12.7 mm (0.50 in) to 13.9 mm (0.55 in) and bells 17.8 cm (7.0 in) to 21.6 cm (8.5 in).

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 the slide stays became tubular. On many modern reproductions round slide stays are much more comfortable to play and easier to make.

A loose connection between the bell stay and the bell is thought key to a resonant bell, and thus a better sackbut sound. Original instruments have a hinge joint. Modern copies with a tuning slide in the bell can need more support for operation of the slide, so either an extra stay by the tuning slide is provided or a joint without play in only one axis is employed.

The original way to make the slide tubes was to roll a flat piece of metal around a solid cylinder mandrel, and the joining edges soldered together. Modern manufacturers now draw the tubes. They also tend to have stockings, which were only invented around 1850. In addition, modern made slides are usually made of nickel silver with chrome plating, giving a smoother finish and quieter action than simply the brass that would have originally been used.

The water key was added in the 19th century, but modern reproductions often have them.