Worn out subframe bushings?

[c-rad]

I have this annoying rattle that is only present under small bumps. It SOUNDS like a heat shield rattle, but that's not possible as I don't have any. I checked the brakes, shocks, springs, anything and everything that could move. I cannot find anything loose. Exhaust is held on with urethane hangers and does not move so it can't be that. So does it sound like a worn subframe bushing(s)? It sounds like it is coming from the driver side rear only.