Channels and Tracks
A
signal by definition is an electronic representation of sound. Microphones
and guitar pickups are used to convert sound to signal. The signal produced
of one microphone will be very different than the signal produced by another
microphone. Reasons for this include the quality and type of the microphone,
and the position of the microphones.
Often when recording, we use more than one mic to capture more 'points
of view'. For example, we would have a mic for the guitar and another
for the voice. Having signals seperated like this is not very useful because
we can only listen to one instrument at a time. It would be better if we ran
both signals through seperate power amps, and joined them to the same speaker.
Then we could adjust the level of one amp to make a better mix. This is in
fact what we use a mixing desk for.
By putting each microphone into a new channel on a mixing desk, the faders
allow us to ajust the level of each microphone independently so as to get
a better 'mix'. The function of the mixing desk is to take several
signals in and mix them together. The desk puts out a single signal that can
go through an amplifier and out the speaker.
When you listen to music, it has already been mixed. It would have originally
been recorded with several mics and then mixed together before being released.
So when you come round to listen to it, you don't have to worry about
adjusting the levels of each microphone, it has already been done. On the
other hand, if we are recording music ourselves, we want to keep each mic
seperate until we finally come round to doing the mix. To do this, each mic
signal has to be recorded seperately. This is why you see '4 track',
'8 track', and '16 track' recorders, and often you will see
some products boasting 'unlimited tracks'.
The number of tracks you have is the limit of how many mic signals you can
have in a recording. It is possible to mix several signals into a single track,
but by doing so, you will never be able to seperate those signals again. So
it is very important that each mixdown is done carefully with the vision of how
it will sound in the end mix.
Glance at a Mixing Desk
The picture below shows a 16 channel Mackie mixing desk. At first glance it looks
like just a bunch of knobs. With a bit of practice you quickly realise it is quite
simple and makes perfect logical sense.
First you have to recognise that the desk is divided into vertical strips, known
as 'channel strips'. Each channel strip has a gain knob at the top and a fader at
the bottom.
Below the gain knob you see two red knobs. These are auxillary send knobs. If you
think of each channel independently, you can see that they each send some of their
signal to the auxillary output socket when these knobs are raised. So by default
these knobs are set to zero, and you only raise them when you want to send some signal
from one of the channels.
Below the auxillary send knobs are two yellow knobs. These are FX send knobs, similar
to the auxillary send knobs, except that the actual level of the signal is proportionate
to the fader. So if the channel's fader is set to zero, no signal is sent to the FX-send
output. In contrast, the auxillary send is often used for supplying a foldback mix to
musicians on stage. This is handy because the foldback mix is not dependent on the mix
that the crowd hears.
Below the yellow are 2 blue knobs for EQ, then one white for Q, then one blue for
low pass EQ. The very bottom knob is a pan knob, allowing you to send the signal to
the left or right channels more or less proportionately to get a 'stereo' effect.
Computers and Multitracking
Computers have been around for several years and are very powerful. A typical
home computer is capable of recording over 24 tracks without problems. In
order to use your computer for recording, you need to have a program that
has been designed to record music. A computer without programs just sits there
and does nothing. The type of software that you use will be determined by
your budget, advice, and the features it provides. Some software is designed
for making music, others are designed for recording and mixing music. Some
are cheap and have less features than others that are more expensive.
Some software is limited by the number of tracks it can hold. I suggest 24
to 32 tracks should suffice, but it is better if you can get 'unlimited'
software, then the number of tracks is only limited by the sheer power of
your computer. It sucks when you run out of tracks and have to start mixing
tracks together.
