Galaxy Note2: How to increase the Call Volume?
When you are on an active call, you can adjust the call volume with the Volume keys.
Touch Extra volume from the active call screen to increase the volume level. When the feature is on, the icon will appear green.
If the audio quality is still not what you would like it to be, you can touch Menu and turn Noise reduction off.
Touch Menu > My call sound to select a personalized call sound.
Choose from Off, Soft sound, Clear sound, Optimized for left ear, or Optimized for right ear.
To find the best call sound for you, touch Phone > Call settings > My call sound.
Touch Personalize call sound and follow the on-screen instructions for the best call sound.