[banjomonster]

85-90dB seems to be the where the concerns for hearing damage start, if sustained for 8+ hours.

Some useful (official) tables and charts: https://www.osha.gov/dts/osta/otm/noise/standards_more.html https://www.osha.gov/dts/osta/otm/new_noise/images/fig3.gif

And this has a nice listing of levels/safe listening times: http://www.dangerousdecibels.org/education/information-cente...