## needed packages: emerge -va media-libs/ladspa-cmt media-plugins/blop
## http://alsa.opensrc.org/index.php/Low-pass_filter_for_subwoofer_channel_(HOWTO)
## make.confbei ALSA_CARDS “usb-audio”
##
##chown root:audio /etc/asound.conf
##chmod 664 /etc/asound.conf
## 5.1 Sound: mplayer -ao alsa:device=my51 -channels 6 dvd://
## 2.1 Sound: mplayer -ao alsa:device=upmix_20to51 blabla.mp3
##
#### -1- ####
# ttable.INTERN.EXTERN VERH
# normally:
# 0 –> front left
# 1 –> front right
# 2 –> rear left
# 3 –> rear right
# 4 –> center
# […]