Bug 304144

If required you can split the channels on one volume control (use the context menu on the slider). It is possble on on sliders (perhaps with the exception of the Tray control). Please check and reprot back.

I can do the way you mentioned. But I still have the only "Master" channel in "select main channel" dialog - without amy splitting

Well, if you can't split then there is nothing to split. Are you sure your master has more channels? If yes, please post the "amixer" output for the affected soundcard (amixer -c 0, amixer -c 1, ...)

Created attachment 73158 [details]
amixer output for the sound card

I can split the Master channel in the KMix dialog, but I think I should be able to select a splitted channel as a main channel in my KMix plasmoid.

There is no KMix Plasmoid, so you cannot set it. Do you mean the popup from the Tray? Please post screenshot.

One can definitely show the separate channels, since some time also finely labeled: http://kmix5.wordpress.com/2011/07/21/enhanced-multichannel-card-support/

Traditionally it is not in the Sound Menu, but the bug reporter did not answer the question whetehr it is about the tray. Newer versions also allow to show it in the tray (not persistent yet, but possible), see attached screenshot.

Thus marking as fixed.

Created attachment 84158 [details]
Splitting channels in the Sound Menu

Git commit 0f7a603e1d327f76dbd6a62d08315b1956794d42 by Christian Esken.
Committed on 20/12/2013 at 10:17.
Pushed by esken into branch 'master'.

Configuration menu is now using Tabs to provide a more standard,
  convenient and pleasing layout
 Sound Menu: Play button reflects playback status and shows either
  "Play" or "Pause"
 Bugfixes and Features (CCBUGS, as most bugs are already closed). Hint: Some
bugs might have actually been alreay fixed ibn KDE4.11 or KDE4.12.

Bug ID	Severity	Summary
Related: bug 317926, bug 20, bug 315383, bug 299477, bug 256854, bug 296951, bug 303608, bug 214854, bug 319600
applet
volume control
position.

M  +9    -5    CMakeLists.txt
M  +41   -20   ChangeLog
M  +5    -1    apps/KMixApp.cpp
M  +167  -238  apps/kmix.cpp
M  +8    -13   apps/kmix.h
M  +3    -0    apps/kmixctrl.cpp
M  +3    -0    apps/kmixd.cpp
M  +18   -12   backends/mixer_backend.cpp
M  +1    -0    backends/mixer_backend.h
M  +229  -150  backends/mixer_mpris2.cpp
M  +23   -6    backends/mixer_mpris2.h
M  +8    -2    backends/mixer_oss.cpp
M  +1    -1    backends/mixer_pulse.cpp
M  +9    -9    core/ControlManager.cpp
M  +102  -15   core/GlobalConfig.cpp
M  +105  -47   core/GlobalConfig.h
M  +65   -31   core/kmixdevicemanager.cpp
M  +9    -4    core/mixdevice.cpp
M  +4    -12   core/mixdevice.h
M  +6    -4    core/mixer.cpp
M  +16   -10   core/mixertoolbox.cpp
M  +1    -1    core/version.h
M  +17   -3    core/volume.cpp
M  +9    -8    core/volume.h
M  +19   -6    gui/dialogchoosebackends.cpp
M  +1    -1    gui/dialogchoosebackends.h
M  +9    -2    gui/dialogviewconfiguration.cpp
M  +37   -10   gui/guiprofile.cpp
M  +27   -24   gui/guiprofile.h
M  +93   -118  gui/kmixdockwidget.cpp
M  +3    -4    gui/kmixdockwidget.h
M  +13   -11   gui/kmixerwidget.cpp
M  +296  -91   gui/kmixprefdlg.cpp
M  +82   -32   gui/kmixprefdlg.h
M  +87   -38   gui/mdwslider.cpp
M  +4    -2    gui/mdwslider.h
M  +69   -42   gui/viewbase.cpp
M  +1    -0    gui/viewbase.h
M  +25   -30   gui/viewdockareapopup.cpp
M  +1    -1    gui/viewdockareapopup.h
M  +4    -4    gui/viewsliders.cpp
M  +1    -1    gui/volumesliderextradata.h

http://commits.kde.org/kmix/0f7a603e1d327f76dbd6a62d08315b1956794d42