I'm curious why do you need an SPL meter to see if you can safely listen to music? Are you planning to go right up to the line where it's too loud, on average, for the average person, to listen to music for extended periods of time?
Well the thing is what is average volume? everyone average is different, all depending on the sensitivity level of your ears. Your avarage might be too loud for me or vi-versa. So i need the meter to give me an objective number so I know. =)
I've been trying to figure out some semi objective way of measuring. As far as I can tell, I just hook up my headphones to my computer then set up some youtube lecture at normal speaking volume and if my music is about the same volume then I know I'm around 60-70 db. Don't know how accurate doing this is though. After that you can just write down what you know is 60db on your foobar and move up from there. Every 5db doubles volume I believe.
Some people have already damaged their ears a bit so it might be helpful for them to know that what they consider "an appropriate comfortable level" is in fact too loud and they're damaging their ears even more.
10db doubles perceived volume. 3db is energy doubling.
SPL meters are a must for any fan of music - many headphones make you want to turn up the volume more and extending listening periods (which i'm sure many of us do) of high SPL are very very bad. there are many charts that government has to abide by for safety reasons..