Here is a soundproofing quick tip dealing with acoustics.
When talking about acoustic soundproofing or acoustic treatment of a room you are looking to improve the quality of sound within the room itself. This is done by breaking up the sound waves and so there is less reflections/bouncing of sound which in return helps eliminates things like echo. Common types of materials that can do this are various foams, certain types of ceiling tiles, and even egg boxes. However just because you are able to put up foam or egg boxes doesn’t necessarily mean that noise from the outside will be blocked. This is a very common misconception that putting up acoustic related items will have the same effect as soundproofing materials.
If you are looking to help stop noise from within the room itself foam and egg boxes can help greatly. You may also want to look at removing various objects in the room that have just a flat surface as sound loves to bounce of these. But if you are looking to stop noise from the outside world coming in, lining your ceilings and walls with egg boxes won’t be able to do what you need. It may reduce it slightly but most likely it won’t be enough if soundproofing is what you’re looking to accomplish. A good sturdy set of curtains will help a lot more against a single-pane window than egg box city. You may also want to invest in soundproof drywall if sound coming in is a huge issue.