“Christensen says people often turn up their headphones 13 decibels higher than the background noise surrounding them. ‘When you’re using earbuds on a plane or train, you’re really pushing the limit of what’s safe. Some trains get up to 80 or 90 decibels loud. Then you’re pushing the limit 13 decibels over that, and that’s when it gets really dangerous.'” Elemental: Something You Don’t Want to Hear About Earbuds.