Originally Posted by rowuk

The reversed leadpipe actually does almost NOTHING. What changes the sound and response is the bell brace and perhaps the bracing on the tuning slide.

There is a myth about airflow which, when you consider the relatively small quantity of air going through the horn, becomes essentially insignificant!

When you move the bell brace back, the bell is more free to vibrate, more free to pass energy through the bell which decreases the amount of energy reaching the audience, but increases the feedback to the player. The player thinks that the horn is more responsive, until they try and fill up a room. They then discover that that was easier with the non-reversed pipe.

Where could a horn with a reversed pipe be interesting? For anyone not needing to blow walls down, anyone using a microphone, or in a studio setting where you do not have to project and fill a huge acoustic space.