Lesson 15 of 15
Acoustic Reflection
Acoustic Impedance & Reflection
When a sound wave hits a boundary between two media, part is reflected and part is transmitted. The fraction of intensity reflected depends on the acoustic impedances and :
ight)^2$$ - $Z = ho v$ — acoustic impedance (Pa·s/m), where $ ho$ is density and $v$ is sound speed - **R** — reflection coefficient (0 to 1) ### Matched Impedance When $Z_1 = Z_2$ (same medium on both sides), $R = 0$ — no reflection, perfect transmission. This is why ultrasound gel is used: it matches skin and water impedances to minimise reflection. ### Large Mismatch Air ($Z approx 413$ Pa·s/m) vs water ($Z approx 1.48 imes 10^6$ Pa·s/m) have such different impedances that nearly all sound reflects — explaining why you can't hear underwater from above. | $Z_1$ | $Z_2$ | R | |----|----|----| | 1 | 1 | **0.0000** (no reflection) | | 1 | 3 | **0.2500** | | 1 | 9 | **0.6400** | | 1 | 100 | **0.9608** (strong reflection) | ### Your Task Implement `reflectionCoeff(Z1, Z2)` returning the reflection coefficient.Web Audio API loading...
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