Brass instrument can be very useful for a 1st or 3rd horn player, who uses the F side less. Another approach was the addition of two sets of slides for different parts of the range. Some euphoniums and tubas were built like this, but today, this approach has become highly exotic for all instruments except horns, where it is the norm, usually in a double, sometimes even triple configuration. Some valved brass instruments provide triggers or throws that manually lengthen (or, less commonly, shorten) the main tuning slide, a valve slide, or the main tubing. These mechanisms alter the pitch of notes
Tuba The conical bore causes the instrument to produce a preponderance of even-order harmonics. A tuba with its tubing wrapped for placing the instrument on the player's lap is usually called a concert tuba or simply a tuba. Tubas with the bell pointing forward ("pavillon tournant") instead of upward are often called "recording tubas" because of their popularity in the early days of recorded music, as their sound could more easily be directed at the recording microphone. When wrapped to surround the body for cavalry bands on horseback or marching, it is traditionally known as a hélicon. The modern sousaphone, named