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Originally posted by Hithe Merinos
reply to post by 123143
The sound level in the room, which actually has the Guinness World Record, is -9 decibels, compared to the average “quiet” room’s 30 decibels. The double-insulated walls are made of steel and foot-thick concrete. Along the walls are also 3.3-foot thick fiberglass acoustic wedges that contribute to the ultra-quietness.