Adolphe Sax s original sopranos were straight. Larger saxes were curved and looped to enable the players to reach the keys and to allow the instrument to be carried. A curved neck allows the soprano sax to be held closer to the body, more at the angle the clarinet is held. This is more comfortable, allows use of a neck-strap, and keeps the bell from hitting the music stand. Most soprano saxes with removable necks are equipped with both straight and curved necks.
Some players prefer the straight neck for playing jazz while standing.
This allows the bell to be aimed at the audience. The curved neck aims the sound down at the floor, and is preferred by many players for saxophone quartet or classical playing. The straight soprano sax, like the clarinet, is more difficult to mic in a commercial setting, requiring two microphones. Micing is accomplished by placing one mic near the bell facing up and a second mic over the left hand. This allows for very little movement by the player.