That totally works. My point was that making it work requires going beyond the text, no matter what solution one prefers.Well, this gets back to my view that a silhouette, a visual effect, cannot itself be heavily obscured. A creature or object might be heavily obscured (or unseen for some other reason), and as a result you might be able to see its silhouette under the right circumstances. As a DM, though, I'm not introducing a silhouette without some good reason because I think it would tend to confuse whether the creature or object could be seen or not, and my goal is to present a clear situation to the players that can be engaged with. Also, a point of clarification, for a heavily obscured creature's location to be known is the default, unless it is also hidden.

I agree that a heavily obscured creature's location is known, if it is within hearing range. A silhouette revealing a creature's location can often be relevant at distances beyond effective hearing range.