Sound proofing is different, and I would "assume" that it wouldn't help the sound out in the way you would want it to. It might just make it so you can listen as loud as you want without bothering anyone else.
I hear that sound proofing is incredibly expensive, so I don't know if he meant real sound proofing.
I hear that sound proofing is incredibly expensive, so I don't know if he meant real sound proofing.