Aerophone Pro AE-30: Can I set the key beforehand for the tones of transposable instruments?

No.
This instrument plays in the key that’s set by the [TRANSPOSE] knob on the back of the instrument by factory default.

Use the following procedure to set different keys for each tone.

1. Press the [MENU] button.
   - The menu screen appears.
2. Use the [–] [+] (</>) buttons to select “Transpose Mode.”
3. Press the [MENU] button.
   - The cursor moves to the lower line.
4. Use the [–] [+] (</>) buttons to select “Scene.”
5. Press the [MENU] button.
6. Use the [–] [+] (</>) buttons to select “Scene Transpose.”
7. Press the [MENU] button.
8. Use the [–] [+] (</>) buttons to set the transpose value.
   　Setting range: -5 – 0 – +6 (in semitones)
9. Long-press the [MENU] button.
   - “Write Scene” blinks.
10. Select “User” with the [-] (<) button.
11. Select the user bank with the [SCENE CATEGORY] knob.
12. Use the [–] [+] (</>) buttons to select which user scene number is used to register the currently selected scene.
13. Press the [MENU] button.
    - The screen for editing the tone name appears.
14. Edit the name of the scene.
15. Press the [MENU] button.
    - A confirmation message appears.
16. To write the settings, press the [+] (>) button. To cancel writing, press the [–] (<) button.
    - After the settings are written, the user scene that was written appears.