Hi lembas,
that was on PartedMagic, a non-free distro which I use once a week because of
the damn Adobe Flash Player® in which I got my lessons.
This option doesn't appear on Trisquel's LiveCD. My notebook's sound chip is
an Intel Cantiga HDMI, and I don't know if there is 100% Free Software which
could handle it 100%.
Alsamixer version is 1.0.24.2; besides, that distro chips with the latest
kernel Linux's version, while Trisquel uses 2.6. I'd try it with Parabola
GNU/Linux-libre LiveCD if (I) it chipped alsamixer and (II) I had Parabola
installed in my dead notebook's HDD.