The container home cannot be sound proof.
There are ways to reduce the overall sound and to muffle some of the external noise, however this is an expensive process.
First, you need to sound caulk around all the outlets, switches, pipes and the studs.
Basically, mass is your sound proof friend. Thicker and heavier drywall will reduce the sound and the space of the interior. Two layers of drywall on each side will have the same effect. Also, adding a heavier fiberglass insulation will absorb the sound as well as staggering your joints. This apparently distracts or shifts the sound vibrations.
The experts say that even though there is value in adding extra insulation, it is neither simple nor cheap and any reduction in sound transmission is not particularly noticeable.
The real question is not “sound proofing”, but “how to reduce noise transmission to a more acceptable level.
Using fiberglass insulation does not significantly drop the noise transmission.
So far what I have discovered is that cellulose insulation is the best for sound proofing because it completely fills the cavities and leaves fewer air pockets for the sound to travel in.
When you compare the cellulose insulation to the traditional fiberglass the cellulose is 3 times more dense, which helps with the sound transmission. However, open spray-on foam is 5 times the price of standard insulation.