Usually when you get serious about listening music you aim to the best quality possible and you should always remember that: The highest quality you'll achieve is the one of your weakest link in the chain. So if you have a great pair of full size audiofile headphones but you try to use it directly from you mp3 player for sure they won't sound as they should. You must build a system for them.
1. Headphones - needless to say that you should have at least a pair of these.
2. Source - the source is what will play your music (audio files, vinyl records, CDs, tapes), like an iPod, turntable, CD player, etc, and feed it to your headphones or to the next link of the system.
3. DAC - aka Digital to Analog Converter, this is a critical part if you are building a digital based system because is what translates the 0s and 1s from your audio files to actual voltage so it can be feed to the:
4. Amplifier - this is the one that will take the signal generated in your source or DAC and amplify it so you can send the signal to the headphones with the right output current, depending on how power hungry your headphones are you should find a matching amp for them.
You'll be thinking now: I don't need all of that when I plug my headphones to my zune or iPod. But in fact sources like that have all of those parts, but miniaturized inside of its case. In the "ideal system" you would like to have the best of each one and that will require to have the best technology for each link, most of the time that requires dedicated units for each part using specialized designs.
Just take a look on the images below so you understand how big a system can get:
Don't freak out and think about how much doe you'll have to spend to build a descent system, there are huge amount of products in the market to fit almost every budget and style. You can buy a headphone amp for just USD$7.50 so it can be quite affordable to begin building a nice sounding rig. Many advanced users will think of other elements for a system like cables, power sources, transports, pre-amps, balanced inputs and many more, but since we are in headphones 102, we'll leave just like that for the moment.
Its always good to have references before putting your money in any piece of equipment, so visit Head-Fi that is the biggest headphones community in the internet and the known universe. Take a look around, ask some questions or if you're shy look the head gear wiki, its a great place to begin with, but it can get intimidating because of the volume of information it has. Also you can go to blogs like headfonia or review sites like 6Moons.
In my next post I'll start to get a bit deeper on headphones styles.