Why use an audio interface? Basically, an interface takes all the various audio inputs and convert them into digital audio data. Yes, your computer will almost certainly have a soundcard but the quality will be lacking if youre using it to make music. Dont forget, computers are mass produced for the wider market, not just musicians, so you need to look at adding another piece of hardware to increase the sound quality and also increase the amount of input/outputs you have, allowing you to connect various other devices/instruments.
Inputs and outputs are the one thing that you need consider when deciding which interface to purchase, as you could come unstuck in the future. For example, if you are just looking to connect one USB controller at the start of your journey, then buy an interface with the sufficient ports for that, what happens when you want to add more to it? Well, you have to buy a new one with more connections... So, just be mindful of where you see yourself in a years time.
One standout interface to look out for is Focusrite and their Scarlett range. Value for money and quality, theres nothing else out there that beats it, plus they look great and are easy to use. There are enough models out there to suit all needs too, with a great way of knowing how many inputs and outputs each have - its in the name. For example, the Scarlett 2i2 (2 in, 2 out), Scarlett 2i4 (2 in, 4 out) and so on and so on.
Click To See THE SCARLETT RANGE
One other interface to look out for, again from the Focusrite team - The Audiohub 2x4. This unit packs a serious punch and even has a warning label about the volume, when you first open the box!! This is a 'must have' if you dont already use a powered usb hub, as it has 3 connections inbuilt.
We have all of the Focusrite models available for demo in our store, so feel free to come and have a look for yourself.