Since an audio interface processes sound outside of your computer, you’ll need at least one pair of outputs to connect to active reference monitors or to a power amp and speaker system. Additional analog outputs are useful for routing audio to external gear like headphone amps, effects processors and mixing boards. For example, you could send a pair of outputs to an outboard reverb unit and feed the processed signal back into the interface inputs. Or you could assign each channel in your digital audio workstation (DAW) to its own individual output and route all your tracks through an analog mixer.

Using Studio Monitors

Although it is possible to monitor through a home stereo or desktop speakers, using dedicated studio monitors will yield much better performance from your setup. If your interface has multiple outputs, you can hook up several pairs of monitors and compare your mixes between them. For more info on setting up and using studio monitors, download Overdub Volume 1.

Headphone Outputs

Dedicated headphone outputs can come in very handy, especially in situations where you're unable to use studio reference monitors. All FireWire and USB interfaces from Avid and M-Audio include at least one headphone output with a dedicated volume control. Multiple headphone outputs are useful if you record with other musicians, and can save you the expense of purchasing a separate headphone amplifier. As we will discuss in a separate section, software control panels can provide I/O control for creating different dedicated headphone mixes for each headphone output—such as a main mix plus a click track for a drummer.

Surround Sound Mixing

Nowadays, most music for video games, TV and film is mixed in surround sound. If you plan on doing multimedia work, get an interface with enough simultaneous outputs to drive a full surround sound system. The M-Audio ProFire 2626 and ProFire 610 each have eight analog outputs—allowing you to hook up seven monitors and a subwoofer and mix in 7.1 surround sound. Both interfaces also feature an assignable master volume knob that lets you control the volume of all speakers simultaneously.

About Insert Cables

An insert cable is wired in a way that lets you send and receive signals over a single cable. Insert cables feature a TRS (tip/ring/sleeve) connector on one side and two TS (tip/sleeve) connectors on the other. The TRS side connects to an insert jack on the audio interface. The "send" TS connector goes to your external device's input and the "return" TS connector goes to your external device's output. This allows signals to be sent and returned using a single cable.

For more information on choosing an audio interface, download Overdub Vol 2.