Spark 86. A sine wave at 528 Hz, originating from Subway Tunnel. Recorded in a cathedral environment, era: 1950s. One of 5555 echoes — sounds no one thought to save.
Name
ECHO #3451 — Spark 86
ID#3451
Rarity
MID:49%
Frequency
528 Hz
X-HI:6%
Wave Type
Sine
X-HI:13%
Resonance
Crystalline
X-HI:5%
Era
1950s
X-HI:5%
Origin
Subway Tunnel