Transmission Loss⚠ unverified
Physics / Acoustics · Compute transmission loss adjusted for receiving-room absorption
Parameters
| Input | Symbol | Unit | Default | Description |
|---|---|---|---|---|
| TL | TL | dB | 1.0 | Base transmission loss of the partition |
| S | S | m**2 | 1.0 | Partition surface area |
| A | A | m**2 | 1.0 | Total absorption of the receiving room |
| Output | Symbol | Unit | Description |
|---|---|---|---|
| result | TLadj | dB | Adjusted transmission loss, in decibels (dB). Returns ``TL`` unchanged when ``S`` is not positive |
The science & history
Understanding the Parameters
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$TL$ — material/construction performance (mass law, coincidence dips, etc. already baked into the number if measured).
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$A/S$ — room-to-partition factor appearing in level-difference formulas ($D = TL + 10\log_{10}(A/S)$ type relations in building acoustics).
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Output — $TL + 10\log_{10}(A/S)$; interpret as NR/level difference style adjustment when $A$ is absorption.
Derivation (Approaching a Proof)
Transmitted power $W_t = \tau W_i$. With incident intensity related to source room levels and transmitted power absorbed in the receive room ($W_t \sim p^{2} A /(\rho c)$ type balances), the level difference between rooms involves $TL = 10\log_{10}(1/\tau)$ plus $10\log_{10}(A/S)$. The registry packs that correction as $TL + 10\log_{10}(A/S)$.
History
ISO 10140 / ASTM E90 laboratory TL and field ASTC/Rw ratings dominate building acoustics practice.
Related Concepts: Insertion Loss, Critical Frequency, Sound Pressure Level, Reverberation Time
Notes: Registry calculator transmission-loss (unverified). Area/absorption adjustment form —
confirm $A$ vs $S$ roles against your code path.