The Flugelhorn is a B-flat Brass instrument that is commonly known as a member of the saxhorn family. It resembles a trumpet, yet differs in the fact that it has a wider and more conical bore.The fingerings for a flugelhorn are the same as for a trumpet, as it is a variation of the trumpet, but with a larger bore, or a saxhorn. Most horns have a third valve slide trigger or loop so that the player may "kick the slide" when playing low D or C#, two unusually sharp notes on the trumpet/cornet/flugelhorn that use the third valve. When the slide is kicked, the extra length of tubing that the air is forced into by the valve extends, lowering the pitch and getting the note in tune.
The mouthpiece on a flugelhorn is more like that of a French horn than that of a trumpet, in a monette form. The french horn mouthpiece is very deep, like the monette mouthpiece on a trumpet or flugelhorn, much deeper than a normal trumpet mouthpiece. Most flugelhorn mouthpieces do not fit trumpets or cornets, and vice versa. Some businesses sell adapters so that the mouthpieces may be interchangeable between instruments. For trumpet or flugelhorn, you can also purchase an ultra-deep rich tone mouthpiece which will help you transfer back and forth between the two instruments without changing your embrochure too much. This mouthpiece can also help trumpet/french horn players with the embrochure change.
This horn is perfect for playing in a setting where you need a trumpet's range, fingerings, and octaves, but do not want the brassy, bold sound associated with a normal trumpet or cornet. This setting may include anything from a church or place of worship, to a wedding, to a casual outdoor concert, to a formal concert hall. Also a good horn to use when playing with trombonists, because the horn sounds exactly like a trombone that plays an octave higher than a normal trombone. This not-as-bold sound makes the horn not ideal for jazz bands in most cases; most jazz players and directors want a sound more bold and direct for a jazz trumpet solo. It can be used in any other setting, however, and makes an excellent French horn substitute.
In conclusion, if you want to play in a church, need a French horn sub, want something less brassy than a trumpet but higher than a trombone, the flugelhorn is for you!