This chapter also shows you how to find the best way for you to work in your environment, with a fair measure of tips and tricks thrown in to make your room sound as good as possible.
Understanding Analog Connections
You’ve probably had a chance to see and use a variety of analog connectors. If you play a guitar or keyboard (synthesizer), for example, you’re familiar with a ¼-inch analog plug. Some microphones use an XLR analog plug. Keeping all these connectors straight can be a little confusing: Why do you have to use one plug for one thing and another for something else? And what’s a TRS plug, anyway?
Read on to discover the most common analog connectors: ¼-inch (mono/TS and stereo/TRS), XLR, and RCA.
The ¼-inch analog plug
The ¼-inch plug is the most common audio connector and one of the most versatile. These plugs come in two varieties: mono/TS and stereo/TRS.
Mono/TS
The plug on a cord that you use for your guitar or synthesizer is an example of a mono ¼-inch plug. The mono part of the name refers to the fact that you have only one channel through which to send the signal. This type of plug is also referred to as a TS plug (short for tip/sleeve). The tip is the end of the plug, and the sleeve is the rest of the metal part. A plastic divider separates these two sections. Check out Figure 3-1 to see this familiar plug.
FIGURE 3-1: A typical ¼-inch plug used for guitar and other electric instruments.
TS plugs are used for a variety of purposes — to go from your guitar to your guitar amplifier (amp), from your synthesizer to your mixer, from your mixer to your power amp, and from your power amp to your speakers. You would expect that one cord could work for all these applications. After all, a TS plug is a TS plug, right? Well, not really. The same plug can be wired differently, and it can carry different levels of power. For example, here are the differences between instrument and speaker cords:
Instrument cord (the one you use for your synthesizer or guitar): This cord contains one wire and a shield — the wire is connected to the tip, and the shield is connected to the sleeve. You need the instrument cable’s shield to minimize noise. If you use a speaker cord (discussed next) for your instrument, you may end up with some noise (that is, you may hear a hiss or a buzz — or even a radio station — coming out of your amp or coming from where you’ve plugged in your instrument). Instrument cords are often called unbalanced lines because of the way they’re wired. An unbalanced cord has one wire surrounded by a braided shield; the wire is connected to the tip of the TS plug, and the shield is connected to the sleeve. The signal is sent through the wire, and the shield is used for the ground. (It keeps the noise down.) You can also find balanced lines, which I explain in the next section of this chapter.
A speaker cord: This cord contains two wires and no shield — one wire is connected to the tip and the other to the sleeve. Because the speaker cord carries a lot more current (power) than the instrument cable, the speaker cord doesn’t have a shield. The signal level covers noise that’s present in the cord. Because you have much less current present in an instrument, you don’t want to use a speaker cord for your instrument.
Stereo/TRS
A stereo/TRS (short for tip/ring/sleeve) ¼-inch plug looks like a stereo headphone plug (take a look at Figure 3-2). The tip is the end of the plug, the ring is the small middle section located between the two plastic dividers, and the sleeve is the rest of the metal part of the plug. A TRS plug can be used for the following three types of cords:
Stereo cord: A stereo cord is used for signals that contain two separate portions: one for the right channel and the other for the left channel. This type of cord is generally wired with the left-channel signal attached to the tip, the right-channel signal connected to the ring, and the shield wired to the sleeve. This type of cord is typically used for headphones.FIGURE 3-2: Use a balanced (TRS) plug to connect professional audio gear.
Balanced cord: A balanced cord is used on professional audio gear to join the various pieces of equipment (to connect the mixer to the recorder, for example). The advantage with a balanced cord is that you can have longer cord runs without creating noise. Why are balanced cords so conveniently noise free? The balanced cord has two wires and a shield inside and has the same signal running through both wires. One signal is 180 degrees out of phase with the other (that is, their waveforms are opposite one another), and when the signals get to the mixer (or whatever they’re plugged into) one of the signals is flipped and added to the other. When this happens, any noise that built up in the signal is canceled out.
Y cord: A Y cord consists of a TRS plug on one end and two TS plugs on the other, forming — you guessed it — a nice representation of the letter Y. This cord allows you to insert an effect processor — a compressor or equalizer, for example — in the line of a mixer (more specifically, into the insert jack of the mixer). Check out Chapter 4 for details on mixers. The TRS plug both sends and receives a signal. This cord is wired so that the tip sends the signal and the ring receives it (see Figure 3-3). The sleeve is connected to the shield of each cable.
FIGURE 3-3: Use a Y cord to send and receive a signal.
XLR
The XLR connector is used for microphones and some line connections between professional gear. This cable has a female and a male end (see Figure 3-4). The cord is wired much like a TRS connector and is balanced to minimize noise. The XLR microphone cable is also called a low Z cable because it carries a low-impedance signal.