I bought acoustic panels online but they didn't reduce noise from my neighbour at all, what went wrong?

Nothing went wrong with the panels — they are working exactly as designed. The problem is that acoustic foam panels absorb sound within a room but block virtually zero sound transmission through walls. This is the single most common and most expensive misunderstanding in soundproofing, and it catches thousands of homeowners every year. The panels you bought reduce echo, reverb, and flutter inside your room, but they do nothing to stop your neighbour's TV, music, or conversations from passing through the shared wall.The distinction comes down to two fundamentally different acoustic problems. Sound absorption deals with how sound behaves inside a room — reducing reflections off hard surfaces, taming echo, and improving speech clarity. Acoustic foam panels, fabric-wrapped panels, and similar products are absorption tools. They are essential in recording studios, podcasting rooms, and home theatres for controlling the room's internal acoustics. Sound blocking (also called sound isolation or transmission loss) deals with preventing sound from passing through a barrier — a wall, ceiling, or floor — from one space to another. Blocking requires mass, decoupling, and airtight sealing, none of which foam panels provide. A typical 2-inch acoustic foam panel has an STC rating of roughly 1 to 3, meaning it blocks essentially no sound transmission.What Actually Blocks Neighbour NoiseTo reduce noise transmission from a neighbouring unit, you need to add mass and decoupling to the shared wall. The standard approach in Ottawa is to install sound isolation clips ($4–$7 each) or resilient channel ($1.50–$2.50 per linear foot) on the existing wall, fill the cavity with Roxul Safe'n'Sound acoustic mineral wool ($1.20–$1.80 per square foot), and finish with one or two layers of 5/8-inch Type X drywall with Green Glue compound ($15–$22 per tube) between them. Every seam, edge, and penetration gets sealed with acoustic caulk. This type of assembly can achieve STC 50–60 depending on the existing wall construction and the specific materials used — a dramatic improvement over the STC 33–36 of a typical standard wall.For Ottawa condo owners dealing with party wall noise — a very common complaint in Centretown high-rises, Barrhaven townhouse complexes, and Kanata condo developments — the Ontario Building Code requires a minimum STC 50 for party walls between dwelling units. If your wall does not meet this minimum, you may have grounds to involve your condo corporation. Document the noise issue, request an STC field test, and reference OBC Part 9 requirements. A professional STC test costs $500–$1,000 but provides the documented evidence needed to pursue a resolution through your condo board.As for the acoustic panels you already purchased, they are not wasted — they will improve the sound quality inside your room by reducing echo and reverb, which makes your own music and TV sound better and can make a room feel quieter overall even if the noise source remains. Just understand that they serve a different purpose than what you needed. For the actual noise from your neighbour, a proper wall upgrade running $3,000–$8,000 per party wall is what delivers results. Sound IQ has more answers about specific wall assemblies, or you can connect with soundproofing professionals through the Ottawa Contractor Directory at justynrookcontracting.com/directory to get an assessment of your specific situation.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:Justyn Rook ContractingRenoMotion Inc.Tiptop ContractingNLC Drywall ServicesHome Front ServicesView all contractors →