Can you believe it? Today, I was insulating. We discovered that the basement suite wasn't as soundproof as we'd like and especially over / near the stair wells. When I started poking around for the cause [this was quite a while ago now], it turns out that the stair landings that separate our space from the basement suite were not insulated at all. So, luckily we have somewhat removable carbonized wood floor boards to remove and I stuffed the cavities with insulation. Hopefully, that helps it a bit more. Otherwise, I'm sure to hear it from the boss.