#keyswitching

And the answer is... this precious little script from Orange Tree Samples. Don't let the words "script" scare you - the people at orange tree have done all the hard work. Here's all you have to do:

1. Download and install. The zip file contains a PDF with very simple and straightforward installation instructions, so I won't repeat them here. Come back when you're done.

2. Open an instance of Kontakt either in your DAW or as a standalone app.  Starting with a clean multi, Go into the "Band" section of the factory library, then into the "Horns" section. Now, drag a "Trumpet" into your multi. Then a "Trumpet Mute". And lastly, a "Trumpet Section". Our goal will be to switch among these patches with keyswitches.

3. At the top of the Kontakt window, click the "Script" button: 

4. The script module now appears at the top of the rack. Click on the "Preset" dropdown, descend into the "User" category, and select "KS Router".

5. The keyswitcher now appears at the top of the rack. Set the "Total Keyswitches" field to 3, since we have three patches to switch through. Next, let's set C1 as the starting note. The easiest way to do that is to click the "MIDI Learn" button and Press C1 on your MIDI controller. 

We're done! Press C1, and then some keys above E2, and you'll hear a trumpet. Now, press C#1, and play a few keys above E2, and you'll hear a muted trumpet. Press D1, play a few keys above C-2, and you'll hear a trumpet section.