The sound card offers several sockets. These are normally a 3.5mm (1/8")
stereo minijack. You can tell if a plug is a stereo jack because it has two
black bands of insulator to provide two separate channels.
If the plug fits…
Look at the back of your computer (unless like clever ol’ me, you told the
man building the computer to supply a harness so all the vital plugs emerge at
the front of my computer). See image above.
INputs
MIC
Microphone is designed specifically for computer mics and not for music.
It
has the quality of a telephone microphone. These plugs are often moulded in pink
plastic. The mic is probably wired for mono. It might look like a stereo plug
with two bands on the plug but
the central portion provides an electrical supply for the microphone.
Line
Line input also comes equipped with the same sized mini-jackplug
but this plug has
two channels so should be capable of recording music from a stereo source such
as a CD. This is often colour coded, green.
If you are going for a top quality audio you will probably
connect your audio recorder to the line. You will need to find a lead with
suitable plugs to link your recorder to the computer. They are easy to find.
'Games connection'
The joystick port is normally a
MIDI interface.
This will let you hook up a keyboard to add music. MIDI has a repertoire of
instruments that you can organise into an orchestra or sound effects.
One word of warning
There is no standard for the wiring of the 3.5mm minijack
connectors so the actual wiring scheme can vary depending on the manufacturer of
the card.
When used as a microphone connector, the tip of the
connector usually carries the audio signal; the centre portion can carry
low-voltage DC power required by the microphone and the sleeve section is used
as the ground connection. The line and output configuration used the centre
portion for the other audio channel.
So, if things don't work,
it might be a plug problem.
Outputs
Line output provides an analogue feed for a recorder or an amplifier for
listening or mixing purposes. There is often a volume control alongside the
output. It is always worth checking this control if everything goes quite. If you have a CD
or DVD on your computer it will also have a line output that will provide enough
power for some Walkman/IPod headphones.
Headphone jack with 1/8" (3.5mm) stereo minijack is also an output. You can use this
for monitoring while recording, but don't use headphones for mixing. HiFi has
1/4inch jack designed for headphones.
Levels
The line input is a standard value of about 200 millivolts. This quasi-standard ensures
components are compatible with most audio equipment. So if you use something
with a 3.5mm minijack plug, you should get quality recordings.
Ironically, professional microphones only put out about 1 millivolt. Computer
sound-cards cannot accept such a low signal level. They require at least 10
millivolts to record anything. So if you want to use serious microphones, you
will need to pre-amplify the signal. There are many low-cost devices are available to
accomplish this.
Connecting
You'll a few tiny holes for audio connections. To make it
easier,
many of the items are colour-coded to help you plug them into the right socket.
These are the computer's equivalent of the connecting jacks on a tape
recorder or VCR, and they work exactly the same way. The plugs on the back of
your other components, called 'RCA' or 'phono' jacks, are much larger. This is a
big clue that the electronics are not well matched to the input or output.
So connect the minijacks to plug a line output into a line input. You plug
the "output" side of one device into the "input" side of the other. To connect
your stereo receiver to your computer, you will need a cable with left and right
RCA plugs on one end and a stereo mini plug on the other.
Most stereo equipment has output for a ‘tape’ or ‘aux’ which is probably about
the right level for the computer. The sockets always appear in pairs, for left
and right stereo signals and they are normally colour-coded white and red.
Recording with a tape recorder or VCR is normally a one button push
operation. Line up the tape and press. It is not quite that simple with a
computer which is, after all, designed to perform many tasks. So you have to do
rather more button pushing.
