Sound mixer: Import Mux? Loopback?

I can hear sound via the docking station’s analogue audio out if I tick the “recording” checkbox for “Import0 Mux”.

Recording just for listening? I don’t understand the names here!

Furthermore, how do I switch off the Laptop’s internal speakers while still hearing something via the docking station’s audio out?

So what exactly do all those mixer’s sliders do?
http://jost.pwp.blueyonder.co.uk/screen/mixer.png

  1. What is the difference between the two “Front” sliders?

Its not the balance, since I do not hear anything if either slider is down or muted, also the first affects all devices (laptop’s built-in speaker, headphones and the docking stations line out, while the second does not affect the headphones. However, there is a separate, functioning, Headphone slider anyway.

  1. What is “Analog Loopback” and “Analog Loopback2” doing?
    I need both ticked to hear anything anywhere.
  2. What is DAC#?
  3. What is Digital?
  4. What is ImportMux#?

Here is my
alsa-info.sh output.

And here is the rest:


> rpm -qa | grep alsa
alsa-utils-1.0.18-6.4           
alsa-tools-gui-1.0.18-1.16      
alsa-1.0.18-8.9                 
bluez-alsa-4.19-1.5             
alsa-firmware-1.0.17-1.42       
alsamixergui-0.9.0rc1-584.91    
java-1_6_0-sun-alsa-1.6.0.u11-1.4.1
alsa-tools-1.0.18-1.16             
alsa-oss-1.0.17-1.43               
alsa-plugins-1.0.18-6.13           
alsa-oss-32bit-1.0.17-1.37
alsa-driver-kmp-default-1.0.19.20090129_2.6.27.7_9.1-5.1

> rpm -qa | grep pulse
libpulse0-0.9.12-9.5

> rpm -q libasound2
libasound2-1.0.18-8.9

> uname -a
Linux mara 2.6.27.7-9-default #1 SMP 2008-12-04 18:10:04 +0100 x86_64 x86_64 x86_64 GNU/Linux

> cat /etc/modprobe.d/sound

options snd slots=snd-hda-intel
# u1Nb.ztWiP1hTtl5:82801I (ICH9 Family) HD Audio Controller
alias snd-card-0 snd-hda-intel

Advance thanks for any clarifications!