Okay John, I am game!
Lets take a look at that curve again and explore why I feel that 90-95 is a better volume to mix at.
One look at the curve shows that 5KHz, a very problematic frequency range in digital recordings, tends to be more responsive to out ears up closer to 100db. Also, at 100Hz, where a lot of the power of a mix exists, at close to 100db, you need about 2 db less of it to sound flat.
Down below 80db, things really start getting squirly because you really need to start bumping up low end to make it sound flat. Taking bad room designs into account, and bad resolution cabling in many home studios, I don't think excessive adding of low end is adviseable! If the mix winds up needing a 2db boost over all in the low end to make it really powerful, I think that is better left to a mastering eq, or for the consumer to boost up a bit on their system.
While the chart shows that you are quite correct sir, I do not feel that it is a good reference volume for mixing because of the above stated reasons. I tend to mix music a bit bass light now and make up for it in mastering where I will not be playing that mix over and over for 10 hours and can make more subjective decisions on low end energy.
Wally, I understand what you are getting at about the least damaging volume, but, as John pointed out earlier, it is good to take frequent breaks while mixing to give you ears a break. If you look over the charts on hearing damage, they usually show how long of exposure you can have to a certain db before hearing damage. The nature of mixing suggests that 1- You will not have CONTINUOUS noise and 2- You will have frequent breaks that last longer then the time it takes to rewind the tape to the beginning.
What I am getting at is that if you are taking frequent breaks, your ears can handle higher db exposure over the period of a day before any hearing damage.
I like to use 90-95db A weighted as my reference level while mixing/mastering. I have found that my mixes achieve far greater smoothness then at lower volumes, and that I don't tend to bloat the bass as much. With frequent breaks, hearing fatique doesn't set in until around that 6-8 hour, so I can get a lot done in that time. Usually the last 2-4 hours I spend on a mix is running mixes with certain parts turned up or and down, and also dealing with mute automation and what not. The first 4-6 hours is where most of my eq and level decisions are made, and they are made when the ears a the freshest.
Ed