if you need to set the default mute and a default volume level..
..add these two lines to the `$HOME/.config/i3/config` file..
exec --no-startup-id sleep 1 && pactl set-sink-mute @DEFAULT_SINK@ false && $refresh_i3status
exec --no-startup-id sleep 6 && pactl set-sink-volume @DEFAULT_SINK@ 15% && $refresh_i3status