your Subject says Sound Proofing, but your question is Acoustic Treatments. they're two totally different issues.
sound proofing requires thickness-density and air tight designs.
acoustic treatments included absorption, diffusion, and room modal treatments.
egg carton stuff is limited in the frequencies they handle. i'd recommend a no buy.
depending on what you're treating, you need a lot more than one type. i'd recommend the book "Master Handbook of Acoutsics" by F. Alton Everest.
regards,
-kp-