Yup. What he said. (I love Wiklpedia)
Also, if you try to use the 2 types of equipment together they don't work quite the way you'd expect.
Say you're using a balanced (+4dBu) preamp and running it into an unbalanced (-10dBv) equalizer, then into your balanced (+4dBu, again) pro audio interface.
You get good level on the preamp so that it doesn't clip then head to the EQ... Holy coe, batman!! Its clipping like crazy! So you turn down the input stage to get things working as they should.
But wait... the level meters on your DAW are reading really low. Hmmm, lets try turing the EQ's output up. That's better, the daw meters look like the preamp meters but the EQ output gain is almost all the way up and its hissing a little...
With proper gain staging and equipment to make up for the 8-11 dB difference (I can't remember what it actually is, I just know its less than the 14 you'd think it is) then you can get the 2 types to work together- but its much easier and sounds better to not because you end up knocking BOTH types out of the range they are designed to work in and lose quality.
Balanced cables can be used for longer runs since they reject RF interference, but for most home studios unbalanced stuff works just fine- the cable runs are short enough that it doesn't really make any difference.
They are different cables, too. Unbalanced are the same as guitar cables- tip and sleave. Balanced are like headphone jack the size of guitar cables- tip, ring, sleave. A lot of "prosumer' equipment will switch between balanced (+4) and unbalanced (-10) depending on what type of cable you use. Nifty, eh?
Take care,
Chris
