As a horn player, you’ve probably been asked this before! We know that the right hand must be inside the bell — but why does it really have to be there?
1. The instrument is built for it!
The modern horn is the product of hundreds of years of refinement, and is literally built around the expectation that the right hand will be in the bell. From a practical standpoint, it helps the player hold the instrument comfortably. In terms of sound, our characteristically dark and mellow timbre is as much a product of our hand as the direction our bell faces. Speaking of which…
2. The hand functions like a music stand or sound shield.
Looking at the other main brass instruments in the orchestra or band, we are not the only ones altering our sound with an object in front of the bell. Sure, horn players might use their hand, but trumpet players are rarely aiming their bells straight out at the audience, trombonists are usually aimed down at an angle, and the tuba and euphonium send their sound up into the air. So why is the bell facing backwards?
3. The horn’s roots are in the hunt.
Horns were originally used for the hunt and played looped around the player’s shoulder while riding a horse. Equestrian practice was to hold the reins with the left hand and horns and weaponry with the right hand. Some believe this is because the majority of people are right-handed. The rider with the horn looped around his right shoulder would be in the front of the hunting party so he could alert the group of game. During this time, there were multiple horn signals recognized. Each had a different meaning and would signal to the hunting party specific information about the game and which direction to go. The rider with the horn would point the bell to the right and away from the horse’s ear, sounding it to the hunting party behind him.
4. The hand helps us predict where our sound will go.
Other brass instruments have the advantage of aiming their sound more or less forward towards the audience. As long as they can see where their bells are pointing they generally know who can hear them. As horn players, we have to be careful not to sit too close to walls, corners, or especially percussion instruments like the timpani. All of these things can distort our sound and make it hard to predict how we actually sound to our audience. Playing into percussion instruments can even hurt our embouchure because the reflected sound is so strong!
5. It’s tradition!
As originally used for the hunt, horns had no valves and the instrument could only be used to play notes in the natural overtone series. Over time, hornists learned that by changing the shape of their hands in the bell they could produce other notes as well. This technique, called hand horn technique, helped the horn to become a valuable member of the orchestra and a viable solo instrument in the 18th century.
Even now that we have valves, there is a major remnant of the old hand horn technique — stopped horn! Think about how different the sound of the instrument is, and remember that we even need to transpose to account for how much we have adjusted the length of our instrument when we close off the bell with our hand.
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Next time someone asks you why you have to put your hand in the bell to play the horn, you can be at the ready with an answer! For advice on right hand placement, check out this link at our Education Site. Karen Houghton and Janet B. Nye posted an excerpt from their book, Recipe for Success: A balanced curriculum for young horn players, in this article that explains proper right hand technique. Happy horn playing! 
— Dr. Sally Podrebarac
Dr. Mike Harcrow of Messiah College kindly shared this chart he uses in his lectures:
Thank you, Dr. Harcrow!