Studio Matrx Monthly · Volume 1 · Issue 1 · June 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
Acoustic Door STC Calculator

Acoustic Door STC Calculator

Enter the source noise and the target level in the room next door. We compute the required noise reduction, the STC class to design to, and which build achieves it — a single acoustic leaf, a leaf with a drop seal, or a sound-lock vestibule — with an indicative ₹ band for India 2026.

The two rooms

We treat the door as the weak path: level next door ≈ source − STC. Required STC includes a 5 dB safety margin so the build clears the target. This ignores flanking (walls, floor, ducts) — a real acoustic survey adds those. Indicative India 2026 only.

Required noise reduction

0 dB

95 dB source − 35 dB target · design to STC 65 (incl. 5 dB margin)

Required STC

STC 65

Recommended

STC 60

Sound-lock pair

Cost band

₹1,53,400 – ₹3,54,000

incl. GST

A sound-lock vestibule is needed.

Two sealed acoustic doors with an airlock lobby between them. Studio / cinema grade. This level is at the edge of what doors alone deliver — pair with isolated walls and a specialist acoustic survey.

Sound-lock pair (two doors + vestibule) — indicative supply ₹1,53,400 – ₹3,54,000 per door (incl. 18% GST).

What each build achieves vs what you need

The dashed line is your required STC (65). Bars that clear it are coloured teal; your recommended build is highlighted in terracotta.

STC values are representative of a well-installed assembly. Real performance depends on seals, threshold, glazing and — critically — flanking paths around the door.

Spec the whole quiet room, not just the door

DesignAI weighs the door against wall build, glazing and flanking paths, and sense-checks the STC target and budget for your theatre, studio or boardroom.

How this estimate works

STC (Sound Transmission Class) is a lab single-number rating of how much airborne sound an element blocks. As a planning rule, the level in the receiving room is roughly the source level minus the STC of the weakest path — usually the door. We add a 5 dB safety margin so the chosen build comfortably clears your target.

STC adds up with mass and seals: an ordinary door is ~STC 25, a single dense acoustic leaf ~STC 40–50, and a sound-lock pair (two sealed doors with a vestibule between) ~STC 55–65. A drop seal at the threshold and compression seals all round are what turn a heavy leaf into a real performer — without them, sound leaks at the perimeter.

These figures are indicative. Acoustic doors are project-engineered and flanking transmission (through walls, slab, ducts and conduits) often dominates — always get a vendor spec and, for studios or cinemas, a qualified acoustic consultant's survey. Cost bands are supply-only; the 18% GST toggle is on by default. Installation, threshold work and isolation detailing are extra.