Lesson Description
Plugging in Guitars
5m 56s
Learn the different ways to get both electric and acoustic guitar signals into your PA systems mixing console.
Video Transcript
Plugging in Guitars
5m 56s
00:14
In this video we are going to be discussing how to properly plug in and connect an acoustic or electric guitar,
00:21
as well as a bass guitar to a PA system.
00:24
We’ll also look at a few techniques for miking guitar amplifiers and acoustic guitars directly.
00:30
Let’s dive right in and get into part 1: The D.I.
00:35
Instruments like electric guitars and basses
00:37
produce an output signal that has a so-called high impedance.
00:41
In addition to being high impedance, it is also an unbalanced signal.
00:47
Remember our discussion on balanced and unbalanced signals from the Audio equipment video.
00:52
For the purposes of this video, all you need to know
00:56
is that in most cases a signal from a guitar cannot be directly sent to a microphone or mixer preamp.
01:03
To make it compatible, we have to convert the signal from high impedance, unbalanced
01:09
to low impedance, balanced.
01:12
To do this we need something called a Direct Box or D.I..
01:17
We discussed this briefly in the “Go with the Flow” video in which we walked through the signal path of a PA system .
01:24
Without a D.I., connecting an instrument such as an electric guitar or bass directly to the PA
01:30
will cause signal degradation and unwanted noise.
01:34
Using a D.I. also allows to use much longer cable runs.
01:38
We start by connecting the instrument into the D.I. with a ¼” TS cable. Also known as an instrument cable.
01:47
The TS stands for Tip/Sleeve, in reference to the hot and common connection points being soldered to the Tip and the sleeve of the connector.
01:57
This is an unbalanced cable.
02:00
The output of the D.I. then needs to find its way to the mixer.
02:03
In some cases, if the location of the mixer permits, the connection can be made directly.
02:09
This is done simply by connecting XLR cables, which are balanced,
02:14
from the outputs of the D.I. to the inputs of the mixer.
02:18
Many times the D.I. will connect to either a digital or analog signal snake on the stage
02:24
that then carries the signal to the mixer. And that’s it. From there, you simply dial in your mixer preamp to the appropriate level.
02:34
It is also good to note that this practice is most commonly used with acoustic and bass guitars.
02:41
While it certainly can be used with electric guitars, it’s not quite so common.
02:46
With that said, if you are dealing with an electric guitar,
02:50
you are probably working with either an amplifier and a speaker cabinet on stage,
02:55
or what is called an FRFR guitar setup.
02:58
This is essentially a digital guitar modeling device that does not require an amplifier and loudspeaker on stage.
03:06
We’ll talk about these both..
03:08
We’ll start with an amplifier and speaker cabinet on stage.
03:12
To get this into our PA system, we’re going to use a microphone to capture the sound coming from the cabinet and deliver that into the PA.
03:21
We’re going to take a look at a couple of common ways that a guitar amplifier can be miked.
03:26
The first thing we’ll need is a dynamic microphone to capture the sound of the guitar cabinet.
03:32
Now, when placing the microphone in front of the cabinet, there are a few things to take into consideration.
03:38
One of them is the distance at which the microphone is placed from the grill cloth of the cabinet.
03:44
The other thing to consider is the position of the microphone in relation to the speaker within the cabinet.
03:50
Placing the microphone directly in front of the speaker driver will produce a different sound than placing it in the middle of the cone
03:57
or even on the outer edge of the cone.
04:00
For most dynamic microphones, you are going to want to place the microphone about an inch, or 2.5cm away from the grill cloth.
04:09
This will cut down on some of the low frequency build up that can occur if the microphone is too close.
04:15
If the microphone is placed directly in front of the center of the speaker,
04:18
you are going to get a lot of high frequency content in the microphone. It will be very bright sounding.
04:25
With the microphone placed in the center of the cone, you will get a good amount of mid-range which will result in a fuller tone than a center mic position.
04:35
On the outer edge, the sound loses high frequency content and is richer in mid and bass content
04:42
The choice you make is fairly subjective
04:44
and also depends on the type of guitar amplifier and speaker driver.
04:49
Ok, now, let’s talk about an FRFR setup.
04:53
Depending on the performer, you might approach this in two different ways.
04:58
In the simplest setup, the modeler would be run direct to the mixer using a Direct Box.
05:04
Sometimes, however the player will use a loudspeaker such as a K.2 or CP series,
05:10
connected to the modeler as an alternative to a standard guitar amplifier and cabinet.
05:15
In this instance, you would use the direct output from the loudspeaker to carry the signal to the mixer.
05:21
That covers the basics. There are more techniques that can be used,
05:25
such as placing the microphone further away from the cabinet to capture a more natural sound and blend the ambient sound of the room in a little.
05:34
Changing the angle of the microphone or even using two microphones and blending the two together in the mix is also possible.
05:43
For the purposes of this video, we aren’t going to get too far into these techniques.
05:48
Well, that covers it for now. I'll see you on the next video
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Plugging in Guitars
5m 56s