Interesting situation. I am a risk consultant by trade, and a guitar player by passion. Here is the risk consultant speech. ALL forms of hearing protection have a NRR (noise reduction rating). It is what the name implies. If a particular hearing protector (muff, plug, etc.) has a NRR of 20, it reduces the sound pressure by 20 dba, or bdc, depending on which scale (not musical scale) the sound pressure rating is measured with. If the exposure is 110 dba, plugs with an NRR of 20 will drop the exposure to 90 dba. Still pretty high. Unless the plugs are inserted correctly, the NRR falls of very rapidly. And I do mean very rapidly.
Sound pressure is not the only concern. The frequencies you are exposed to and duration have a big impact on the damage that may be done to your hearing. Generally, lower frequencies do not cause as much damage as higher frequencies (generally). Duration is important. Typical exposure is measured and expressed as TWA (time weighted average). Exposure would be measured as 85dba TWA, or 90dbc TWA, etc. Unless the duration is eight full hours, readings on a correctly calibrated sound level meter must be taken at periodic intervals and calculations done to determine the actual estimated exposure levels. The calculations are not complex. The fewer readings, the greater the margin of error. If only a few readings are taken, the margin of error increases. OSHA standards DO NOT apply to an audience, but liability standards do. Exposure over 90dba TWA is considered harmful. The db rating is exponential, not linear, whether measured on the a scale or the c scale. Think of the proverbial Richter scale for earthquakes.
Bottom line is, your hearing is a valuable sense, and can easily be damaged by high sound pressures, especially if the sound has a lot of high frequencies or is very concussive. IMHO, everyone in your band should be wearing some kind of hearing protection. There are many types of hearing protection available, from cheap foam plugs to costlier protection that can be frequency selectable. A lot of people harm their hearing in small incremental doses. The damage cannot be reversed. For a small fee, you can get an audiogram done annually. Loss of high frequencies is usually due to noise exposure. Loss of mid-frequencies is usually due to a medical condition.
As for your long term exposure, hearing damage is like smoking. One ciggi will not kill you, but a bunch every day sure will. Same with hearing loss. Small incremental damage to your cilia (little hairs in your ears) will cause profound hearing loss, that cannot be corrected. Ask yourself what kind of shape your ears will be in 20 years from now. I hope this helps amigo. You should take your hearing protection very seriously.
