Timbre
The tone is "fatter" and usually regarded as more "mellow" and "dark" than the trumpet or cornet. The sound of the flugelhorn has been described as halfway between a trumpet and a French horn, whereas the cornet's sound is halfway between a trumpet and a flugelhorn. The flugelhorn is as agile as the cornet but more difficult to control in the high register (from approximately written G above the staff), where in general it "slots" or locks onto notes less easily. It is not generally used for aggressive or bright displays as trumpets and cornets often are, but tends more towards a softer and more reflective role.
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