TL;DR: Sound travels between rooms by two routes. Airborne sound (voices, music) travels as pressure waves through the air and through walls. Structure-borne sound (footsteps, subwoofer energy, plant vibration) travels as vibration through the building's solid structure. Effective soundproofing has to deal with both — and they need different fixes.
Airborne transmission
Airborne sound passes through a partition by making it vibrate and re-radiate on the other side. You reduce it with mass (heavier partitions move less), decoupling (so the two faces don't drive each other), cavity absorption, and airtight sealing — even a small gap leaks a lot of sound.
Structure-borne transmission
Structure-borne sound is vibration travelling through floors, walls and frames — the thump of footsteps, or low-frequency energy from a subwoofer coupling into the building. Adding surface mass barely helps; the fix is isolation: breaking the vibration path with resilient mounts, floating floors and decoupled structures.
| Airborne | Structure-borne | |
|---|---|---|
| Examples | Voices, music, TV | Footsteps, subwoofer, machinery |
| Travels through | Air & partitions | Solid structure (vibration) |
| Main fix | Mass, decoupling, sealing | Resilient isolation, floating |
Why a cinema needs to address both
A home cinema generates serious low-frequency energy that couples straight into the structure, so subwoofer "thump" reaching the rest of the house is usually structure-borne — which is why simply adding a dense wall lining often disappoints. The C-ATS Isolation System targets both paths as a discipline separate from acoustic treatment.
FAQ
My subwoofer is heard through the house — airborne or structure-borne?
Usually structure-borne: low-frequency vibration coupling into the building. Mass alone won't fix it; you need isolation.
Does sealing gaps really matter?
Yes — for airborne sound, small air gaps undermine an otherwise good partition. Airtightness is essential.
Is this the same as acoustic treatment?
No. This is soundproofing (isolation). Treatment improves sound inside the room. See the difference.