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 But I turned up my speakers, moved the Youtube slider all the way up, and set my system volume to max. Still can't hear above a whisper. But it's only on some of your videos. On others, they're nice and loud.

Yeah. the first few videos were a painful learning process. The initial videos were uploading at over 900 meg. I've got 'em down to 12 meg.

Not being a sound guy...I had my system set for noise reduction and auto input gain... thinking  "Oh. That must make the sound better." 
Psyche.

I appreciate the offer ... there is an option for the video owners that allows for collaborative input. I'll send the link.