Lesson Description
Go with the signal flow
5m 45s
Learn the basics of how audio signals flow between the various pieces of equipment in an audio system.
Video Transcript
Go with the signal flow
5m 45s
00:15
In this video we are going to learn about signal flow.
00:19
Signal flow is the path that the audio signal takes as it moves through an audio system.
00:24
Having a healthy understanding of how the signal flows through an audio system
00:29
and knowing which direction a signal is flowing will help us to set up an audio system as well as being able to troubleshoot it.
00:37
In general, every piece of equipment will have an in and an out, through which the signal passes.
00:43
As you connect the various components of the system together,
00:47
the signal will flow in and out of each piece and then to another.
00:52
This is called the Signal Chain. At this level, the signal is flowing in one direction.
00:59
Let’s take a look at a very basic audio system example to start off.
01:04
We have a single audio source, for instance a microphone. And then we have a mixer and some loudspeakers.
01:10
As the performer sings or speaks into the microphone, it is converted into an electrical audio signal.
01:18
The signal then flows out of the microphone and into the mixer.
01:22
And then the final step is the signal flows out of the mixer into our loudspeakers.
01:29
We’ll use active loudspeakers for this example to keep it as simple as possible.
01:34
A mixer typically will have a stereo output which is presented as a signal Left and signal Right channel.
01:40
These are each connected to the appropriate loudspeakers that have been designated to be house right and left.
01:46
Now let’s extrapolate this out to a slightly larger system.
01:50
We’ll be using the same concept of signal flow however.
01:54
In this example let’s say we have two microphones,
01:58
plus an acoustic guitar, bass and a Cajon.
02:02
We know what to do with our first microphone because of example 1.
02:05
All we have to do to complete this larger signal flow is continue with that process.
02:11
We connect the second microphone to the mixer. Now we connect the acoustic guitar and bass.
02:18
Ok. Because we are now connecting instruments to our mixer, we have to introduce another piece of equipment,
02:26
the D.I. box, which we learned about in the last video.
02:30
If you missed that or need to refresh, go back and check the audio terminology video.
02:36
For this video we'll simply say that the output of an acoustic guitar or bass guitar is not quite compatible with a mixer input.
02:44
The D.I. bridges that compatibility.
02:48
Alright, so now that we have our D.I. introduced to the system,
02:52
the signal is going to flow out of the acoustic guitar,
02:56
into the D.I. and then out of the D.I. into mixer.
03:01
We repeat this step for the bass.
03:04
Our Cajon is more than likely going to use an additional microphone or maybe two.
03:09
Now, just like in the first example the signals are all mixed together and processed by the mixer
03:16
and the signal then flows out of the mixer’s left and right outputs to the left and right designated loudspeakers.
03:23
And we can keep going!
03:25
Let’s look a larger more complicated setup.
03:29
We now have four microphones, an acoustic guitar, an electric guitar, bass, a full drum kit and maybe even a string section.
03:39
All of the steps from the first two examples still apply.
03:43
We connect all of our vocal and drum microphones into the mixer,
03:47
we’ll also likely be using microphones to capture the electric guitar cabinet on stage as well as the strings.
03:54
We have our D.I. boxes with our acoustic guitar and bass.
03:59
Now, instead of connecting these directly into the mixer, let’s introduce another piece of equipment.
04:05
Maybe our stage is a significant distance away from where our mixing console is setup.
04:11
Running a few dozen individual cables over a long distance is not efficient, and can become untidy.
04:18
So we’re going to use a signal snake. The snake gives us a patch panel with a bunch of inputs just like those you’d find on the mixer
04:27
And all of the inputs are bundled together in one large cable
04:32
which then breaks out into individual connectors for each of the inputs on the patch panel at the other end.
04:39
Or a single connector if the stage box and snake are digital .
04:43
We connect everything into the snake panel on the stage
04:47
and then connect the other end of the signal snake to the corresponding inputs in the mixer.
04:52
Input 1 on the snake input panel will connect
04:55
into input 1 on the mixer via the output connection 1 on the other end of the snake.
05:01
Keep going until all of the instruments and mics are connected.
05:06
Now the mixer will mix and process all those incoming signals and the signal will flow out of the mixers outputs.
05:13
But instead of going directly to the loudspeakers this time, we are using a larger passive PA setup.
05:20
This requires amplifiers. So the signal flows out of the mixer, into the amplifiers
05:28
and then from the amplifiers out to the loudspeakers.
05:32
So, even though we have larger setup, we can still easily follow the signal path.
Downloads and Links
Go with the signal flow
5m 45s