I already reported this several buids ago, i think this only apens in systems powered by kx drivers. This appens with Mc because MC control's the main volume and not an "internal" volume control. Feel free to try the release 3535b of KX drivers to see if this correct the bug. Don't really know if this is a Driver's problem or an MC problem.
[changes]:
Added support for 24/96 playback and recording for Audigy2-based boards (EXPERIMENTAL)
Improved power management support
Improved hardware compatibility with certain audio cards
Fixed bug with AC97 contoller power management
Improved SMP / HyperThreading support (EXPERIMENTAL)
Improved real-time panning quality
Added option to choose Wave panning method (true pan or balance) - by command-line tool
Added support for horizontal peak meter
Added a shortcut for the peak meter to the kX Mixer page
Improved IO Status window
Improved 'mute speakers when headphones are plugged-in' option
Added option to choose the desired speaker spatialization method (by using command-line tool)
kX DSP window enlarged
Added real-time update option for kX Editor and kX API (EXPERIMENTAL)
Updated Filter effects (may be not 100%-compatible with previous)
Added APS Compressor + with Side Chain input
Added MX6 (custom mixer) DSP effect (described here:
http://www.kxproject.com/mx6_help.phpAdded high-quality headphones positioning effect (HpSp
Updated XRouting effect to support 8-point spatialization
Prolog and Epilog effects re-written to support amplification (EXPERIMENTAL
Improved kX Mixer indication for inputs & outputs (levels measured in dB
(NOTE: if you have any pre-3535 setting files, the new prolog/epilog
features won't be available until you upload new prolog/epilog effects
into the DSP. Resetting settings will upload the new effects automatically
Danish translation added
Polish translation updated
Improved System Tray icon
BETA Update not a Full Releasehttp://kx.maincore.nl/beta/kxdrv3535b-update.exe