On Friday Carroll and Thomas brought the ladder down from the intermediate chamber and rehung the curtains that were taken down when the new windows were installed in mid-May, in the hope that this might mitigate the excessive sound levels.
At the June 4 practice with all eight bells going, the level was measured at almost 88dB, above the widely accepted threshold of 85dB. Decibels are a logarithmic scale, with a difference of 10dB defined as a factor of 10 between the two power levels; the 3dB difference from 85 to 88dB represents a factor of almost exactly two, so that 88dB is twice the power of 85dB.
At today’s service ringing, with all eight going, the meter showed slightly more than 76dB, less than one-tenth the power at 88dB. Lower would be better (the NIH recommends less than 75dB) but at least this is out of the range in which permanent hearing damage is inevitable over time.
The curtains make a substantial difference and we will leave them up until a permanent and more attractive solution can be arranged.