User:Billw58/Connecting an Instrument

Gale 06May11:

• General: Think it needs cautionary mention about not connecting to mic port (mic but not line port will be common on Windows). But (without there being any control to change level) mic ports on Windows net/notebooks *do* nowadays seem to give some kind of stereo and not massively distort when line-level is connected. It has been a frequent complaint about the LPs / cassettes tutorial that you can get "reasonable" results plugging line level into mic on small form factor machines. True on my netbook, too.
• Keyboard: Should it have a sentence about what to do about hearing the keyboard if you use the headphones jack? Software playthrough?
• Guitar: Maybe I was tired but I couldn't get my head round the 2nd paragraph so tried to rewrite it.
  • Bill: The sentence you deleted advised users to find a mono 1/4" to mono mini-plug cable instead of cobbling one up using a 1/4"-to-miniplug adapter. It's fine to leave that out.
• I get the impression that sometimes the direct guitar output isn't strong enough for computer line-in so that needs to be covered as do the issues of connecting the output to the mic port if it is strong enough.
  • Bill: In my experience the output of an electric guitar with the volume control all the way up is about 100 mV - lower than the "standard" IHF level, but too high for a mic input.
• Also I think connecting the guitar to an amp or an FX pedal and thence to computer needs to be mentioned. People with USB or acoustic guitar need to be pointed elsewhere.

Bill 06May11: Tweaked to take into account the above comments.

Connecting a keyboard or guitar to your computer

Generally speaking you will want to connect these instruments to the line input port on your computer. However there are some PC notebooks/netbooks where it has been reported that the microphone input port will tolerate line level inputs (and sometimes provide a stereo input as well). You should always try the line input port first, and only go to the microphone input port if you cannot get an adequate recording level using the line input port.

Keyboard

If the keyboard has RCA jacks on the back then the best way to connect it is with a dual RCA to stereo mini-plug cable as shown below, plugged from the RCA output jacks on the back of the keyboard to the line input port of the computer.

	A Stereo Mini plug to dual RCA cable

If the keyboard has 1/4" jacks on the back (usually provided to connect the keyboard to a guitar amplifier) you will need to create an adapter cable using a dual RCA to stereo mini-plug cable, and two RCA to 1/4" adapters.

	An RCA to 1/4" adapter

Plug the RCA plugs into the RCA jacks on the adapters - you now have a dual 1/4" to stereo mini-plug cable.

If the keyboard has neither of these options, but does have a 1/8" stereo headphone jack, the easiest way to connect it is with a cable with a stereo mini-plug on each end, plugged from the headphone output of the keyboard to the line input port of the computer. You will lose the ability to listen directly to the keyboard using headphones, and any internal speakers will probably be muted. You can get around this using Software Playthrough in Audacity, but that introduces a delay between the time you play a note and the time you hear it. This topic is covered in more detail in a following section.

Guitar

This section is about connecting an electric guitar, bass, or acoustic guitar with an electrical pickup installed, to your computer. If you want to record an acoustic guitar with a microphone, or record the sound of your guitar amplifier using a microphone, then you should read the section on connecting a microphone to your computer.
If you have a "USB Guitar" then you can skip ahead to testing the input connection for your operating system.

Generally the output level from an electric guitar (or electrical pickup in an acoustic guitar) is sufficient to drive the line input port on a computer. Turn the volume control on the guitar all the way up. You will need a shielded adapter cable that goes from a 1/4" mono plug (to plug into the guitar) to a mono mini-plug (to plug into the computer line input port).

You probably have a guitar cable for plugging the guitar into an amplifier, and you may be tempted to buy a 1/4" to 1/8" adapter instead, plug it into the computer line input then connect the guitar to the adapter using the cable - don't do this! This creates a heavy, stiff cable hanging off the back of your computer - the slightest tug in the wrong direction could damage your sound card!

If you cannot get a good recording level when connecting to the line input port (explained in a following section on setting recording levels in Audacity), you can try the microphone input on your computer (if you have one). Beware of overloading the microphone input. You can turn down the volume control on your guitar to compensate for the extra amplification in the microphone input port, but hum and noise may increase in comparison to using the line input port.

Most effect pedals are designed to deliver about the same volume to the amplifier as the un-effected guitar sound (the volume you get when the effect is bypassed). Thus you can connect your guitar to a pedal and then connect the pedal to the computer.

Some guitar amplifiers include a "direct output" for feeding the amplifier sound to recording or PA systems. Amplifiers designed for stage use and that include this feature will usually have a microphone-level balanced output using an XLR connector. Connecting this output to your computer microphone input is beyond the scope of this document - talk to the folks at your local music store.

There are USB audio interfaces specifically designed for connecting a guitar to a computer. Again, talk to the folks at your local music store.

Next Step - test the input connection

Click on the link for your operating system:

• Macintosh
• Windows
• Linux