Change the sound output settings on Mac
You can play sound through your computer’s internal speakers, your display’s speakers (if it has speakers), or through speakers, headphones or other equipment plugged into your Mac or available wirelessly through AirPlay.
On your Mac, choose Apple menu > System Preferences, click Sound, then click Output.
Select the device you want to use in the list of sound output devices.
All sound output devices available to your Mac are listed, including the computer’s internal speakers, devices plugged into your computer’s sound port (), USB speakers and AirPlay devices.
For any device plugged into the computer’s sound port, choose Headphones.
Do any of the following to adjust your sound output settings:
Adjust the balance or volume: Drag the volume slider.
Show a volume control in the menu bar: Select the “Show volume in menu bar” tickbox so you can turn the volume up or down from anywhere.
To set a separate volume for alert sounds, click Sound Effects.
Depending on your Mac and the devices you use, you may be able to set other volume options using the Audio MIDI Setup app.
If you use apps that have volume controls (for example, Music or iMovie), their settings can only be equal to or less than the computer’s output volume. They do not override the settings you choose in Sound preferences.