How to choose an audio interface

By Laura B. Whitmore

At some point, you have probably thought about doing some recording using your computer or laptop. If you've finally decided to jump in, then you probably need an audio interface. An audio interface's purpose is simply this; it helps you bring audio signals into your computer. Here are some of the things you need to think about when choosing the best interface for you.

In or out of the box?
Most audio interfaces are external devices that you can connect to your computer using a high speed USB or Firewire connection. However you can actually install an audio interface into your computer using an interface card. You’ll have to open up your computer and use one of your card slots.

Connection options
It’s important to know what kind of ports your computer has available for connecting your interface. Your choices are: USB 1.1 – if you have a computer that is over four years old or so, you might have this port. USB 2.0—the faster, newer version of USB, has been a standard port for more recent computer models. And finally Firewire – fast and widely available on newer Macs.

The ins and outs
Think about what are you going to plug into your interface and how many you’ll plug in at once. If you are recording multiple instruments at once, you’ll want more ins. And don’t forget about outs! Use these to connect your computer to some great sounding monitors, a PA or even your stereo. The important thing is to plan ahead and get what you think you’ll need up front.

Sample rate
When you convert audio through an interface, it does the conversion at a particular sample rate. The standard sampling rate is 44.1 kHz, the same resolution that is used for audio CDs. However, if you are working in a high-end recording situation, you might want to consider a higher rate like 192 kHz resolution and a more high-end interface.

Microphone essentials
All microphones require their signal to be boosted so that the levels are hot enough for recording. If your interface has a microphone in, it will have some pre-amplification for this purpose, but if you prefer to use a condenser mic, you’ll want an interface that also has phantom power. This is not included in all interfaces, so you’ll have to look for it.

Software choices
Check to make sure that the interface you choose is compatible with the software you are using for recording. For example, Digidesign’s Pro Tools will only work with a Digidesign or M-Audio interface, depending on which version you are using. Also, some interfaces come with recording software, so read the fine print!