sndctl

v1.3.1 (2023) by Nate Weaver (Wevah)
https://derailer.org/

A small utility for controlling sound output from the command line on macOS.

$ sndctl -v volume
$ sndctl -b balance

Volume and balance are from 0.0 to 1.0, translated to volume as min/max, and to balance as left/right.
For balance, l, r, and c, are aliases for 0.0, 1.0, and 0.5, respectively.

Capitalize V or B to display the volume or balance.

Pass --visual with V and/or B to display volume and balance as ASCII sliders.

List output devices and supported properties with --list/-l (colored if CLICOLOR is set):

$ sndctl -l
44: Display Audio
    has volume:  yes
    has balance: yes
65: External Headphones
    has volume:  yes
    has balance: no
53: MacBook Pro Speakers
    has volume:  yes
    has balance: no

(See the man page/help for more options.)

I originally wrote this to easily correct the output balance after rebooting:

$ sndctl -b c

Note: Getting/setting the balance on some outputs on Apple Silicon macs doesn't work.

Wevah/sndctl

sndctl