Moan. A sine wave at 440 Hz, originating from Subway Tunnel. Recorded in a anechoic environment, era: 1980s. One of 5555 echoes — sounds no one thought to save.
Name
ECHO #1331 — Moan
ID#1331
Rarity
MID:33%
Frequency
440 Hz
X-HI:7%
Wave Type
Sine
X-HI:13%
Resonance
Brittle
X-HI:6%
Era
1980s
X-HI:8%
Origin
Subway Tunnel