Mass loaded vinyl wins when the goal is blocking airborne sound from passing through a wall, floor, or ceiling — acoustic foam doesn't block sound transmission at all; it only absorbs reflections inside a room.

MLV and acoustic foam solve completely different acoustic problems. Mass loaded vinyl adds mass to a structure, which is what physically resists airborne sound transmission — voices, traffic, machinery hum. Its STC rating of 27 (for Soundsulate 1 lb MLV) reflects real blocking performance. Acoustic foam, by contrast, has an NRC rating rather than an STC rating because it absorbs echo and reverb within a space. Installing acoustic foam on a wall will make a room sound less reflective; it will not stop sound from moving through that wall to the next room.

  • Soundsulate 1 lb MLV carries an STC rating of 27 — a measure of airborne sound blocking through a structure.
  • Acoustic foam carries an NRC rating (typically 0.5–0.95) — a measure of in-room sound absorption, not transmission blocking.
  • Soundsulate LAG composite (MLV laminated to quilted fiberglass decoupler) achieves an STC rating up to 29.
  • Acoustic foam has near-zero effect on STC — adding it to a wall does not meaningfully raise the assembly's transmission loss.
  • MLV weighs 1 lb per square foot at the standard grade; acoustic foam typically weighs under 0.1 lb per square foot.

How to Choose

  • Pick Soundsulate 1 lb MLV if: your problem is airborne sound — voices, traffic, or machinery — traveling through a shared wall, floor, or ceiling into another room.
  • Pick acoustic foam if: you need to reduce echo, slap-back, or reverb inside a single room — a home studio, podcast booth, or practice space with hard reflective surfaces.
  • Pick Soundsulate LAG composite if: you need both transmission blocking and absorption in one layer — pipe wraps, duct enclosures, or any application where mass plus decoupling is required.
  • Pick both MLV and acoustic foam if: you're building a recording space that must isolate outside noise AND control internal reflections — they address separate problems and don't overlap.
  • Pick neither alone if: your problem is impact noise — footfalls or structural vibration — which requires decoupling and underlayment, not mass or absorption alone.