Apple has recently applied for a patent that would automatically reduce the volume of iPods to safe levels, slowly reducing the volume over time to protect ears. Doesn't that sound like a great idea? It may in theory, but not necessarily once it's implemented.

iPods currently already have parental volume controls built-in, due to increasing pressure to protect kids' ears from the damaging effects of earbuds pumping loud music directly into their ears, but when we tried using this control on my daughter's earbuds, we ran into a problem. The current volume control only affects the maximum volume setting of the iPod and does not adjust for individual songs. If you or your child get music from multiple sources besides just ripping CD's, like downloading free music or listening to podcasts, you'll find that not all audio files have the same volume level. iTunes attempts to find the average volume of the song and adjust it accordingly, but most people still have to adjust the level for certain songs, and while this can be done manually in the "Options" tab, it can't be done permanently on the iPod itself.

Consequently, if your child is using an iPod in the car and has the volume slightly higher to drown out the vehicle noise or the podcast Mom and Dad are listening to, some songs will not be loud enough, and the parental controls will need to be adjusted or disabled for that one audio track.

Using the iPod in the car creates another problem. We use an FM Modulator to listen to iPods over our minivan's sound system. To do so effectively, we have to have the volume of our iPods turned up all the way, and we still generally have to turn the volume up quite a bit to hear podcasts. Limiting the iPod's volume because the iPod thinks we're using headphones would just force us to turn up the car radio dial even more, introducing static and lower playback quality. 

If Apple wants to do this correctly, they need to adjust not the volume setting, but the maximum decibel level. That way, parents could set a certain level, and songs that suddenly get too loud would automatically be dampened or "compressed" so the loudest parts of the song would be adjusted on the fly in mid-song. This would also be useful for podcasts that have really loud transition music (e.g. Leo Laporte's Tech Guy radio show podcast). I'm not sure whether the iPod hardware is capable of doing this, but iTunes could certainly tag a song as it's scanning the volume level to set not just one level, but multiple changes, offering the option to turn off this feature for those who would rather take their hearing into their own hands or car stereos.