When using the JS-10 with headphones you will notice that the built-in speakers will remain on. This could be distracting if you want to play in a quiet setting. Here's the steps you need to take to turn off the built-in speakers.
- Press the [MENU]
- Use the rotational dial to go to "AUDIO SETTING"
- Press [ENTER]
- Use the rotational dial to go to "SPEAKER"
- Press [ENTER]
- Use the rotational dial to switch between "ON" and "OFF"
Once you have set the speakers to "OFF" you shouldn't hear anything else come out of the built-in speakers.