Audio connections

There are several types of audio interfaces (sound cards). CardBus (PCI), USB/USB2 and FireWire are the most common. Laptops can use an audio PCMCIA card. Many audio interfaces also have MIDI inputs and some have built in MIDI synthesizers as well. This section covers the various audio connection options.

Analog and digital Inputs

There are two basic types of audio inputs, analog and digital. Analog inputs allow you to connect a guitar, mic or other instrument to your computer directly. The audio interface converts the analog input to digital. Digital inputs allow other digital devices to connect directly to your computer. Common digital inputs include external analog to digital converters, popular guitar processors like the Line 6 POD, and other digital recording systems like the ADAT decks. Analog inputs are very common, and are standard in virtually all consumer sound cards (the ones that come with your computer). Digital inputs are becoming more popular and are very common on professional and mid-level, “prosumer” interfaces. Analog inputs allow you to record a mono or stereo signal (assuming you have a stereo input) while digital inputs allow you to record 1 to 8 signals depending on the type of digital connection.

The following table describes the various types of analog and digital connections you may encounter.

Cable	Type	Description
	1/4 inch TRS	Balanced analog connection
	XLR	Balanced analog connection Microphones, professional audio equipment
	1/4 inch TS	Unbalanced analog connection Guitar cable, “Hi-Z”
	1/8 inch “Mini” Plug	Balanced analog connection Headphones, desktop computer speakers
	RCA - Phono	Phono analog connection Turntables, analog cassette recorders
	SPDIF	Stereo digital connection
	Optical (Lightpipe)	Stereo digital connection
	MIDI	MIDI connection

Read your hardware documentation carefully to determine what kind of connections you have on your audio interface.

To connect an electric guitar or keyboard to your computer

If your sound card has a 1/8 inch input jack (built-in sound cards that come with your computer usually do), plug your 1/4 inch mono guitar or audio cable into a 1/8 inch stereo adapter, and then plug the 1/8 inch adapter into the microphone input or line input jack on your computer sound card. If you are connecting a keyboard, the audio cable must go from the keyboard’s audio out or line out jack to the sound card input jack. 1/8 inch stereo adapters are available at consumer electronic supply stores.

Or

If you use a professional or “prosumer” sound card, there is probably a 1/4 inch input jack on your sound card or audio hardware interface that you can plug your guitar cable or audio cable into.

To connect a microphone to your computer

If your sound card has a 1/8 inch input jack (built-in sound cards that come with your computer usually do), and your microphone cable has a 1/4 inch plug on the end, plug the mic cable into a 1/8 inch stereo adapter, and then plug the 1/8 inch adapter into the microphone input jack on your computer sound card. 1/8 inch stereo adapters are available at consumer electronic supply stores.

If you use a professional or “prosumer” sound card, there is probably a 1/4 inch input jack on your sound card or audio hardware interface that you can plug your mic cable into.

If your mic has a cable with an XLR plug on the end, and your sound card or audio hardware interface has a 1/4 inch input jack, plug the mic cable into an XLR-to-quarter inch adapter, and then plug your mic cable into your audio hardware. If your audio hardware has an XLR input, of course it’s better to use that.

You can also plug your mic into a mixer or pre-amp, and connect the mixer or pre-amp to an input jack on your audio hardware. This is usually the best method.

That's it! Now that your instruments are all set to go, you can restart your computer and turn on your keyboard, guitar, and microphone.

For a complete description of audio input options, see Hardware setup.

Next topic: MIDI connections

 

See:

Changing I/O devices