How to Select an Audio Recording Interface

Choosing an Audio Recording Interface for Your Studio

MBox 2 Mini
MBox 2 Mini. Courtesy Avid, Inc.

At the heart of any home recording studio is your choice of audio recording interface. This piece of equipment handles input and output of audio from your computer; it's a lot more than a sound card.

Many audio recording interface options are available, but selecting one is confusing. When you shop for a new audio recording interface, you may not need the most expensive interface if you are a hobbyist. Look at the types and number of connectors you need, channel types and the interface compatibility with your digital audio workstation (DAW) software before you select a recording interface.

How Many Inputs Do You Need on an Audio Recording Interface?

The number of inputs and outputs you need for your studio depends on the number of tracks you want to record at one time. Conventional wisdom says a solo musician needs at least two microphone preamp inputs—that way you can record vocals and an instrument at the same time. If you plan on recording drums, you'll need at least four preamp inputs for kick, snare and stereo overheads, and chances are you'll want more for good drum sounds. Small groups or bands need four to eight inputs. Engineers who record bands benefit from at least 16 inputs.

No matter your current needs, assume on the high side when it comes to the number of inputs. You'll be surprised at how your needs mysteriously expand. It's better to have extra inputs if you can afford them. As you get better at recording, you'll be ready for more inputs as you tackle multiple instruments at once. In general, the more inputs, the more expensive the interface. 

Input Chanel Types

In addition to knowing how many inputs an interface has, you'll need to be sure the types of those inputs are aligned with your needs. The input channels on most audio recording interfaces are usually some combination of  the following:

  • Mic - Used to connect a mic directly to the interface
  • Line - Used with an outboard mic preamp as a mic channel
  • Optical - Used with both an outboard mic preamp and digital converter with ​an optical app as a mic channel.
  • DI - Used with electric guitar or bass
  • MIDI - Used with keyboards or MIDI controllers

Recording Interface Connector Types

USB is the most common connector for home studio recording interfaces. Even if you're recording only one or two channels at a time, high-speed USB is a must. Old, slow USB versions cannot safely support the quantity of bi-directional data involved. Select the most current version of USB for your interface.

Recording interfaces with Firewire, which is becoming less common, Thunderbolt and PCIE connectors are all faster and more expensive than interfaces with USB connectors. They are also more suitable for professional or high-end studio use. 

Other Considerations

  • Most audio interfaces support most popular DAW software, but it doesn't hurt to confirm that the interface you are considering for purchase does exactly that. Better safe than sorry.
  • Interfaces come as small desktop units that sit next to your computer and as large rack-mounted interfaces. For beginners and most home studios, the desktop unit is usually the best choice because it is inexpensive and requires no mounting or peripheral devices. You just plug it in and start recording.