Sense-Certainty

I'm still a little uncertain of what sense-certainty can be, and I was wondering what any of you might have to say.

My original understanding was that sense-certainty is the immediate and instantaneous awareness of sensual experience. In other words, sense-certainty consists of all the sensual data available (sight, sound, smell, taste, touch) at a particular time t. But this can't be right, because some (if not all) of our senses exist in time and not at a particular moment. I am thinking particularly of sound; sound is vibration and thus does not exist in any particular now, and cannot be included in the sensual data available at any time t. I suspect touch operates much the same way, and perhaps the other three, depending on how one looks at them. At any rate, sense-certainty cannot be aggregated sense-data (or something to that effect) at a particular time because sense-data can't be produced in a single moment.

My next guess is that sense-certainty is not any particular kind of sensation, but maybe only our ability to have conscious experience of sensation. Of course, that might be Hegel's point in the first place.

Any thoughts?