Mass-loaded vinyl and absorptive panels only correct frequency response in the room. It does very little to isolate you from outside noise. They will only make

Mass-loaded vinyl and absorptive panels only correct frequency response in the room. It does very little to isolate you from outside noise. They will only make that noise more balanced across the frequency spectrum and do practically nothing to prevent noise from entering or leaving the room. It's a common mistake to think that room treatment and room isolation are the same thing. But they're two different problems that require two different approaches to solve.