Idea to soundproof window wells from the outside?

Hi everyone, I've been evaluating my basement sound issues, and the largest sound problems are through the construction-grade windows in the basement, up the window wells, and out through the plastic window well covers. Instead of the covers, has anyone tried building special window well enclosures to block the sound? Either that, or maybe there are some pre-fabricated window well covers/doors that are up to the task of blocking sound? I tried searching the forum, but didn't come up with much. Almost everyone seems to be building heavy-duty window inserts to go inside the basement. However, why not in addition to that (or instead of) add an exterior sound blocker? Something like the attached picture... I'm not sure how much sound those steel doors would block though. Perhaps building something out of a layer or two of thick wood would be better, with some roofing shingles to help it withstand the weather? Has anyone tried this or have plans they could share that worked out well? Other ideas? Thanks, Alan

I'm not sure how much sound those steel doors would block though. Perhaps building something out of a layer or two of thick wood would be better, with some roofing shingles to help it withstand the weather?

There are two key issues you should take into account: mass, and seals. "Mass" as in making them heavy, and "seals" as in making them absolutely air-tight. I would aim for a mass of at least 4 pounds per square foot (20 kg/m2), and more if possible, across the doors AND the supporting structure. Plus good-quality seals all around, at least two complete sets. - Stuart -