boy that would be a long thread to explain what your asking. Try doing a bit of research on it.
For the basics from what i understand
You need to notice first that they are different db measurements. I believe one is dbu and the other is dbv. from what i know -10 is what normal consumer electronics use. The cabling for this is done with 2 wires inside the cable, a + and a -. To power these two wires you need a certain amount of voltage through the cable, although i dont remember the numbers for this. +4 however uses 3 wires in a cable, there is a +, a -, and i think a ground (though im not sure if they really call it ground). This requires almost double the voltage to send the power through this type of cable, thus raising the the db of the signal. I guess you can think of the +4 and -10 thing as a ratio of some sort. They are put into this to equal it out to a standard 0. I dont know too much about electronics and cabling and such but this is kinda how ive understood it, although i might be way off or i might be close but skimming the edge.
I believe the only thing with the hi and lo impedance is that older mics had a high impedance and had to have preamps that could push the gain louder for that impedance. I guess later they changed to low impedance to have the opposite effects. Again, i dont really know for sure on this one.
unbalanced cables are considered -10 cables because they usually use only 2 wires. There is really nothing special about these except from what i know, they lose signal the farther they go from noise. balanced cables are used mainly for very long distances. They way they work from what i know, is their is the 2 cables that work just like an unbalanced cable, with an extra 3rd cable that cancels out noise and stuff, which is why it can be ran long distances.
Again, i want to tell you that i do not know these things very well, but this is how ive always understood them. I would love for someone to come and correct me if im wrong so i can also understand them better.
danny
