How to set Windows audio balance using Python

In our previous post we showed how to set the Windows audio volume using pycaw.

First, we install the library using

pip install pycaw

Note: pycaw does not work with WSL (Windows Subsystem for Linux)! You actually need to install it using a Python environment running on Windows. I recommend Anaconda.

In order to set the audio balance, we can use volume.SetChannelVolumeLevel(...):

from ctypes import cast, POINTER
from comtypes import CLSCTX_ALL
from pycaw.pycaw import AudioUtilities, IAudioEndpointVolume
import math

# Get default audio device using PyCAW
devices = AudioUtilities.GetSpeakers()
interface = devices.Activate(
    IAudioEndpointVolume._iid_, CLSCTX_ALL, None)
volume = cast(interface, POINTER(IAudioEndpointVolume))

# Get current volume of the left channel
currentVolumeLeft = volume.GetChannelVolumeLevel(0)
# Set the volume of the right channel to half of the volume of the left channel
volume.SetChannelVolumeLevel(1, currentVolumeLeft - 6.0, None)
# NOTE: -6.0 dB = half volume !

Note that by convention, the left channel is channel 0 and the right channel is channel 1. Depending on the type of sound card, there might be as few as 1 channel (e.g. a mono headset) or many channels like in a multichannel USB audio interface. use volume.GetChannelCount() to get the number of channels.