What Is the Mass Law Acoustic Sound Transmission Loss (STL) Calculator?
Sound Transmission Loss (STL) measures the decibel reduction in acoustic power passing through a partition barrier.
How Does the Mass Law Acoustic Sound Transmission Loss (STL) Calculator Work?
Calculates acoustic impedance inertia resistance from panel surface density and frequency.
Mass Law Acoustic Sound Transmission Loss (STL) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
ext{STL} approx 20 log_{10}(m cdot f) - 47.5 ext{ dB}, quad au = 10^{- ext{STL}/10}
Acoustic mass law for random-incidence sound transmission loss through limp panels.
How to Use the Mass Law Acoustic Sound Transmission Loss (STL) Calculator
- Enter the wall surface density in kg/m² and the frequency of interest in Hz.
Step-by-Step Example Calculation
Drywall Partition Sound Isolation
Input Values:
surfaceMassDensityKgPerM2:22
frequencyHz:500
Worked Steps: Computes field STL of 33.3 dB with only 0.046% of incident sound power transmitted.
Understanding Your Result
Higher STL values indicate superior soundproofing; transmission coefficient indicates the fractional energy transmitted.
Factors That Affect the Result
- Panel stiffness, resonant panel modes, and critical coincidence dip frequencies where bending waves match airborne sound.
When Should You Use This Calculator?
- Architectural soundproofing, building code STC rating predictions, and industrial noise enclosure specification.
Assumptions & Limitations
- Valid in the mass-controlled region below the critical coincidence frequency; assumes limp single-leaf partition.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Theoretical mass law approximation for field sound incidence.