If you have an external audio device connected to the Audio Inputs on the SPD-SX, and you're not able to monitor the sound or view signal levels while in the Sampling menu, then it's possible that the Audio Input / Out parameter is set incorrectly. Use the following steps to choose "MASTER" for the Audio Input/Out setting:
1. Press MENU.
2. Cursor to highlight the "SYS" icon, and then press ENTER.
3. Cursor to highlight "AUDIO IN/OUT," and then press ENTER.
4. Highlight "AUDIO IN," and then press the + or - button to choose "MASTER."
5. When you're finished, press the KIT button to exit. The new setting is saved automatically.