The Brass family 

This family includes from highest to lowest pitch, the trumpet, horn (or french horn), trombone and tuba.  Structurally the brasses are similar.  Each has a cup-shaped mouthpiece and ends in a flared bell.  Air travels through a tube which is shorter for instruments of a higher pitch and longer for instruments of a lower pitch.  The length of the air column in which the air can travel is changed with valves (the trombone uses a slide).  However, changing the length of the air column does not solely determine the pitch of a tone.  To produce pitches of different pitches with the same fingering, players must also adjust the muscles of their lips and the force of their breath.
 
The brasses can be bright in timbre like the trumpet, or rich and mellow like the horn.  Each of the brasses can be muted to make a nasal tone, gentle or raucous, depending on the force used in playing.