Go with the signal flow
| Site: | QSC |
| Course: | House of Worship Audio Training |
| Book: | Go with the signal flow |
| Printed by: | Guest user |
| Date: | Tuesday, 17 December 2024, 5:56 PM |
Description
Lesson Description
Learn the basics of how audio signals flow between the various pieces of equipment in an audio system.
Video Transcript
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.