Check if package pulseaudio-alsa is installed
Manjaro i3 can have a problem when installing PulseAudio that additional package pulseaudio-alsa is not installed (a recommended optional dependency)
The package creates the ALSA configuration for PulseAudio to be default instead of a specific hardware device
If the package is installed and audio is not working, please post more information
pacmd dump
amixer -c1