pcb 3.5mm stereo jack

anybody know how they exactly work ? does it just pass the analogue signal on.

idea being to interface my ipod to this pass through some filters which il making a graphic visualiser from then output the sound to some speakers ?

or would a mic be a better option and just amplify the signal before it passes through the filters?

Yes, it is normally just a connector for analogue signals. iPods will connect to standard speakers etc.

TRS connector - Wikipedia, the free encyclopedia

An ipod has a very low power output that drives earphones, not speakers. Its output can drive a stereo amplifier that drives speakers.

What is a "graphic visualiser"? A video screen? An audio spectrum analyser using many filters?

what i mean by graphic visualizer is like the things of media players or itunes that vary due to the frequency of the song being played, just i am making a hardware version.

hopefully a miniture version of this https://www.u2r.co.uk/wp-content/gallery/posters/a4-sub-focus.jpg

idea being ipod - aux cable - filters to a micro controller to control an array of leds dependant on the frequency then an aux out to speakers.

just trying to figure out how the jack works as it has 5 contacts and im waiting on a pin layout but it just looks like a switch.

cheers

The photo you posted does not do anything. I don't know what it does.

Google Images has thousands of Audio Spectrum Analysers. If you want one then please don't call it what you wrongly called it.