Watching 2 mkv video simultaneously using LAV splitter but the second video no sound at all

As title say,

Do i need some tweak on the settings ?

I even try pause the first video and try play the second video but still no sound

MPC-HC options > Internal Filters > Audio Renderer > uncheck "exclusive mode"
That should normally already be disabled by default.

If that does not solve it, then:
Windows Control Panel (control.exe) > Sound > select default device > Properties > Advanced > Disable the two exclusive mode options

Thanks !!

Work like charm

Did you accidentally enable exclusive mode in the player settings? Or did you actually need to disable it in Wndows settings?