https://blog.offline-net.com/2011/08/19/ubuntu-7-04-alsaadvanced-linux-sound-architecture%e3%82%92%e3%82%a2%e3%83%83%e3%83%97%e3%83%87%e3%83%bc%e3%83%88%e3%81%99%e3%82%8b/