Anyways I'm a Trombone player (don't worry I come in peace ^_^) who is a big fan of the French Horn. And I am considering learning how to play it. And the mouthpiece seems to be really small, at least compared to my mouthpiece, and I just wanted to ask is playing it hard?

It's a bit harder because horn plays higher in its harmonic series so the pitches are closer together.

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GOOD LUCK!!!

It's not really harder, it is just more precise.