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eng.sound-transmission-class Calculator
Calculates wall Sound Transmission Class (STC) from transmission loss data across frequencies and applies ASTM E413 contour fitting. STC 50 walls block normal speech — STC 65+ is needed for music practice rooms. Standard gypsum stud walls achieve STC 33–36.
Inputs
Transmission Loss 125
Reference formula or conversion factor shown for context.
Transmission Loss 500
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Transmission Loss 1000
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Transmission Loss 2000
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Transmission Loss 4000
Reference formula or conversion factor shown for context.
Results
estimated STC rating
A standardised quality or risk rating on the applicable scale.
STC interpretation
Qualitative summary of what the computed numbers mean in practical terms.
midband TL average
The arithmetic mean -- sum divided by count.
typical uses
Reference formula or conversion factor shown for context.
full STC
Reference formula or conversion factor shown for context.
STC 50+
Reference formula or conversion factor shown for context.