The printer may be set up to use Quiet Print Mode. The engine speed gets reduced in this mode and it can make the printer whistle like this. If you know it's own or aren't sure, turning it off may get rid of it if it annoys you that much.

To do this on the 2 line LCD printer:

• Go to System Settings
• Find Quiet Print Mode
• Change it to Off

If the noise remains, the motors are causing it. I would do your best to ignore it but if it bothers you they can be replaced but it's a difficult repair.