Well... regardless of how right my gut was... Anyway, I've gone into properties(advanced) for my soundcard and have tried every possible combination of the two available (Hardware acceleration 'n Sample rate conversion quality) and have noticed zilch effect.
I've also gone thru each of the option I have for Preferences\Audio\Output: Sound Blaster Audigy, CyberLink Audio Renderer, Default DirectSound Device, Default WaveOut Device, and DirectSound: Sound Blaster Audigy.... no successes with any of these either.
Then I went back through the listed preferences once again also including every variation of the two slider mentioned earlier, No Joy.... I am ashamed to admit it, but what I've done to circumvent the problem is to run the various file thru
AlltoAVI and created a new .avi to watch instead. Even this has some quirks. With all the .mkv files i've done this way I've had to either force no skipping of frames or hardcode each frame individually. After which the exsisting audio track sync'd perfectly..... so I'm thinking its a viz problem.
I will keep futzing with it, hope that down the line this all will help somone.
And many thanks adicoto, really.