volume control
Refers to the function or mechanism for adjusting audio volume, commonly used in software, devices, and audio equipment.
You can adjust the volume using the icon at the bottom right of the screen.
This app has a volume control feature.
音量 means 'volume' (sound level), while 音量調節 specifically refers to the act or mechanism of controlling that volume.
調節 is a general term for 'adjustment' or 'regulation'; 音量調節 narrows it to audio volume adjustment.
Compound of 音量 (おんりょう, 'volume') and 調節 (ちょうせつ, 'adjustment').