How to Play the Horn
The road to good horn tone is long

How does a horn produce the notes of a scale? There are so many tubes, and the player's hand in the bell may also seem a bit strange at first.
The length of the instrument changes if one chooses to play the long F tube or the short B♭tube. With this instrument, the F tube length is 370 cm without pressing any of the levers. Pressing the first lever causes air to pass through the first branch tube, extending the overall length by 45 cm, and the second lever adds 22 cm, while the third lever adds about 74 cm. The longest possible length is 510 cm, with all the levers pressed.
Depending on the model and manufacturer, these numbers will change, but the B♭tube is generally about 275 cm long, and with all three levers depressed, this increases to 385 cm.

Though it depends on the individual, the middle to high ranges are mostly played with the B♭tube, but middle C or other notes that are too low to play with the B♭tube are generally played with the F tube. The longer the tube the harder it is to get the higher notes correct, so when playing high notes, it is a safer bet to play the shorter B♭tube rather than the longer F tube.

As you can see, the tube has become very long.

The air flow on a double horn