Acoustic Doors

Optimizing the Performance of Acoustic Doors

In the age of open floor plans and chiming cell phones, silence is golden. That may explain the growing demand by architects and building owners for acoustic doors.

Acoustic doors are engineered to prevent a specific amount of sound from passing through a door. They have been common in loud environments such as manufacturing facilities and music studios for decades, but they have become increasingly popular in office buildings, hotels, and schools too.

STC Ratings

A door’s Sound Transmission Class (STC) rating specifies how much sound is prevented from passing through the door. The higher the STC rating, the more sound resistant the door.


What can be heard

25 Normal speech can be understood easily and distinctly
30 Loud speech can be understood fairly well; normal speech heard but not understood
35 Loud speech audible but not intelligible
40 Onset of “privacy”
42 Loud speech audible as a murmur
45 Loud speech not audible
50 Very loud sounds such as musical instruments or a stereo can be faintly heard
60+ Superior soundproofing; most sounds inaudible



SDI has developed a variety of resources for architects, specifiers and distributors on acoustic doors below.


The Benefits of STC Rated Doors When Acoustics are a Priority

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FAQ from Architects on Acoustic Doors & Specifications

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SDI 128

Guidelines for Acoustical Performance of Standard Steel Doors and Frames

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Covers STC, wood grain finish, blast and tornado resistance, and more

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The Acoustic Series: A Focus on Fenestration

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Manufacturers usually have proprietary cores for their acoustic doors. It’s important to specify to the performance rather than the core material because that’s what matters. It could be to an STC or OITC value, or even the performance at specific frequencies.

The acoustic door manufacturers below have been audited to meet SDI standards.