Surge. A sawtooth wave at 440 Hz, originating from Subway Tunnel. Recorded in a open air environment, era: 2010s. One of 5555 echoes — sounds no one thought to save.
Name
ECHO #2867 — Surge
ID#2867
Rarity
MID:46%
Frequency
440 Hz
X-HI:7%
Wave Type
Sawtooth
X-HI:9%
Resonance
Phosphoric
EX:2%
Era
2010s
X-HI:7%
Origin
Subway Tunnel