The blue jack on sound cards...

[Master.America]

Every sound card I've had has had at least three jacks. Of these are a green jack (labeled OUT), a pink microphone jack, and a blue jack (labeled IN). What exactly is this blue jack for?

 

[Sicloan]

well actually it depends on the sound card. On my (onboard) sound card, it came with a program that lets me choose what i want to install. For a 5.1 sound system, there are 5 channels, 1 slot for the sub and center channel , 1 for the front speakers and 1 for the rear speakers. The reason is with the ouput jacks, each one supports 2 channels. so 3x2 equals 6 channels which is how many a 5.1 sound system has.

Now the blue one labeled in can be used for multiple things, but i'm guessing you could try a 4 piece speaker system or something like that with it.

 

[OMGLOLWTFPWN]

Usually in means you can put something in it to record from/play out of your computer speakers. Maybe if you had a portable cd player you could put it in "in" and play it through the computer speakers (assuming you don't have headphones) or record without the use of mic. Just a guess though.