I'm learning Linux and I've installed Arch 4.7.5 on Virtual Box 5.1.6.I've installed alsamixer and tried running speaker-test but it didn't work. I've found this guide which partially fixed my problem. Now when I run this test I hear static in both speakers, but only the first time I run it. If I try running it again, it forever shows me 0 - Front Left and doesn't do anything. Maybe this is a bug and I should report it? 
speaker-test works only once
arch linux;virtualbox;alsa