I posted this in the science and technology forum, but I think it can fit in here as well. Anyways, I have two questions, but I think the answer for them might be the same.

First, how does a radio station (say FM) transmit data to my car antenna? If the radio station broadcasts at 90.1 MHz, but the sound I want to hear is in the Hz or KHz range, how does this work? It seems like there would have to be two frequencies going on at the same time. Would the data be like a small signal on the larger signal that is the carrier signal?

Similarly (I think), in a song, if a bass drum is hit while a singer is singing, how can both of these frequencies be carried on the same line at the same time? In other words, how can one signal come through an antenna, and result in a subwoofer and tweeter each vibrating at different frequencies, but at the same time.

I am currently studying electrical engineering in school, so I do have some idea of how various types of passive and active circuit components work and behave at different frequencies. All this to say, hopefully there's no need to break answers down to a grade school level.

it's not as simple as sending a sound from one place to another.

there is an encoding and decoding process that makes the original signal translate into the sounds that come out on the other end.

Can you elaborate a little more?
Edit: Or at least provide some links that I can read?

This post was edited by SexualNinja on May 20 2014 09:12pm

Right, but both frequencies come from the same place. How?

http://electronics.howstuffworks.com/radio-spectrum.htm
http://electronics.howstuffworks.com/radio8.htm
http://stereos.about.com/od/stereoscience/a/AMFMRadio.htm

any of those should be fine.

But in order for your speakers to "know" what sound to play, they require a signal from the radio station. My question is, if the radio station is broadcasting at the fixed frequency of 90.1 MHz, how do they also send the variable signal that the speakers require?

I'm about to hop on Skype for a while, but I look forward to continuing this discussion. This is certainly a question that has been bugging me for a while, so I'm glad I have some people to help me figure it out.

it doesn't send the signals directly to your speakers. this is why you have the receiver and not just an antenna. without the receiver to decode the signal into the proper sound waves you wouldn't get music to your speakers.

Google it hopefully it helps