I spotted an interesting article today via Boingboing. If you have a digital audio player such as an ipod or other mp3 player, and you listen to music that has been copy protected, your battery life can be drastically reduced. When music stores add drm to a song they encrypt it with a digital key. In order for a device to reproduce the music it must first decrypt the file and then play it. Every digital audio player has a microprocessor embedded in it, the device is basically a small computer. The process of decrypting is actually very processor intensive. The harder a processor is working, the more power it is using. If you are listening to a song purchased from iTunes, Napster, Rhapsody, Sony, or any of the other stores that sell copy protected music. In an article over on CNET they discovered from testing various music players, that devices playing songs encoded with Microsoft’s WMA 10 drm they lost up to 25% of battery life compared to playing un-protected mp3 files. Apple uses a different drm scheme called Fairplay on there AAC music files. Only ipods can play these files and are optimized for them. Compared to straight mp3 the ipods had about 8% less battery life.

How do you avoid this extra battery drain? Don’t give your money to music stores that sell copy protected files. There are plenty of stores that sell unprotected mp3 files (usually at higher bit rates too) like emusic.com, mp3tunes.com and magantune.com. Of course you probably won’t find the likes of Britney Spears and other current top 40 hits at those stores, but I personally consider that to be a positive. Go check out these stores. Browse around and listen to the samples. Discover some new music. Support the artists (because itunes and other drm stores sure don’t). You also get the benefit of being able to play these mp3 files on any device rather than being locked into a specific brand.