How much better is optical audio - Airport Express?

While the main purpose of digital cables for sound is to provide true 5.1 surround sound with movies, it does provide some advantages over 2 channel composite cables when listening to music. Bascially what the digital optical cable will give you is a clearer signal and better frequency responce. The thing is though, unless you have very nice speakers and a very nice receiver, it isn't going to be a hugely noticable difference. Im a bit of an audiophile, so I use digital optical or digital coaxial cables (which are about the same quality) in just about everything I can with my sound system. But if you spent less than $500 or $600 on your sound system, dont expect to hear anything huge. Plus, if you are using this with airport express, that means you're probably streaming mp3s, which are a compressed quality on their own. You won't get too much difference in sound when playing mp3s. Its all up to how much money you want to burn. Might be worth the extra

Cheers 😎

Edit: Oh. missed that. No, you wont gain any more independant channels. It'll still only be 2 channel music. Closest thing you could get to multiple channels is if you have Pro Logic II support on your reciever.