Audio Interfaces take all the various audio inputs and convert them into digital audio data.
Though that sounds straight-forward, this was easily the most confusing part for me as I began the quest to design my own home studio.
This piece of hardware will end up being the front end for nearly all the inputs that will be used in your home recording studio.
Digital audio, electrical analog audio, and MIDI data will all come together in this great sonic melting pot.
It acts as the central hub for all the various Audio Signals in your setup... taking them from your finger tips and vocal cords and into the digital realm.
By handling all the audio input and output signals of your system it performs the same function as the Sound Card in a typical computer.
The main differences are that Audio Interfaces typically have mic preamps onboard, provide Phantom Power for condenser mics, and have easy-access external inputs and outputs.
So technically the terms Sound Card and Audio Interface could be used interchangeably.
But for our discussion let's define Sound Cards as hardware internally mounted to your computer, while a studio Audio Interface is an external hardware unit connected via USB or FireWire.
Though there are many options, there are 6 main features to consider when choosing Audio Interfaces:
- Analog / Digital Converters
- Number of Microphone Preamps
- Number of Inputs/Outputs
- Interface Type
- MIDI Capability
- Mixing Capability
Read on for a more detailed explanation of each criteria on our list.
For everyone else I strongly recommend having a firm grasp of the main issues that are outlined below before shopping for specific units.
This may be the single most important decision when creating your home studio, so it's critical to have a firm grasp of how these work and what they are used for.
These provide the ability to take the electrical signal from your microphone or instrument and convert it into the digital signal that computers can understand.
Just as Doc Brown needs the Flux Capacitor to make time travel possible... so do we need A/D converters to make digital recording a reality.
Audio Interfaces are the quickest and easiest way to introduce this essential component into your setup.
A/D converters are described as a set of 2 numbers: a bit depth (i.e. 16-bit, 24-bit) and a Sampling Rate (such as 44.1 kHz, 96 kHz, etc).
This set of values represents the maximum bit depth and sample rate possible with a given interface, you can always set them lower as you choose.
A bit depth of 24-bits and sampling rate of 48 kHz are solid target values to shoot for when shopping around.
A common mistake is to assume that a mixing console will provide this capability, but unless it has a USB or FireWire output it will not.
Furthermore you'll have to pay top dollar (~$1500) for a digital mixer with the ability to record each input to it's own dedicated track, something even moderately priced audio interfaces can provide.
The more affordable digital mixers (~$300) will only output the Left/Right main outputs through the USB or FireWire interface.
