The first sousaphone, a non-production prototype made by J. W. Pepper & Son, Inc., had an upright bell, hence the nickname "rain catcher" because of its shape.

Later production versions differ primarily in two ways: a bell shaped to face forward with a larger flare and a bell diameter of 22 to 28 inches (56–71 cm), and a "goose-neck" leadpipe which offers greater adjustability of mouthpiece position at the expense of tone quality.

Both the sousaphone and helicon have a wide and roughly-circular shape leaving a large empty area in the center, and are designed to be worn around the player's body, with the inside of the coil resting on the shoulder.

The range of the B♭ helicon is two octaves below that of a B♭ cornet,[1] thus similar to the more common B♭ bass tuba (though generally without the additional valves and other optional features sometimes seen on tubas, meaning that a few notes in the lowest range are unavailable on the helicon).

The Slovenian composer Igor Krivokapič invented a new family of Helicons which were produced by the German manufacturer Melton: