If you are wiring speakers, you must know the correct way to do it. If it is your first time wiring speakers, you may be confused about which speaker wire is positive and which is negative. There are different signs and methods you can use to determine this.
Which speaker cable wire is positive, and which is negative? Speaker wires may be colour-coded, and the manual for the speakers will tell you which is positive and negative based on the colour-coding. Otherwise, they may be see-through, and the silver wire will be positive, and the copper wire will be negative.
By looking at these two options, you will generally be able to figure out which wire is positive and which is negative. However, you may still be wondering about other methods to determine this or why it is important to tell these wires apart. Keep reading to learn more.
A Primer On Speaker Cables
Before we get to the main part of this article, let's consider the makeup of a speaker cable.
Speaker cables carry speaker level signals, the strength of which (in volts) varies largely depending on the speaker. Signal levels range anywhere from a few volts for small speakers up to 100 or more for larger loudspeakers and subwoofers.
Due, in part, to the relatively high signal levels (and high signal-to-noise ratio), speaker signals run unbalanced. This means that there are two conductors/wires in the cable. One wire carries the signal while the other acts as ground.
Individual speaker transducers typically convert mono audio signals rather than stereo signals.
The positive and negative terminals of a speaker are designed to accept the same mono signal, only in opposite polarity. The positive terminal connects to the positive signal wire (the mono unbalanced signal has positive polarity). The negative terminal connects to the negative signal wire (the mono unbalanced signal has negative polarity).
Recommended reading: How Do Speakers Produce Sound? (A Helpful Beginner’s Guide).
Other Methods To Know Which Wire Is Which
If your speaker wires aren’t colour-coded or see-through, or you don’t have the manual for your speakers, you might still be wondering how you can tell the wires apart. There are a few different methods you can use to determine this.
- 9-volt battery test: Use a 9-volt battery connected to a battery clip with red and black wires.
- Multimeter: Use a multimeter to determine polarity.
- Visual or physical clues: Look for visual or physical clues to tell them apart.
9-Volt Battery Test For Speaker Wire Polarity
You can perform a simple 9-volt battery test to determine which wire is positive and which is negative.
- Find a 9-Volt battery with a matching battery clip with red and black wires indicating positive and negative.
- Take the speaker wire that you think is negative and connect one end to the speaker.
- Briefly connect the positive (red) wire of the battery clip to the other speaker.
- If you correctly picked the negative speaker wire, you should hear a scratching noise coming from that speaker.
- Make sure to mark the negative wire so that you can tell the difference in the future.
If you do this quick 9-volt battery test, you should be able to determine the difference between your positive and negative speaker wires.
Testing Speaker Wire Polarity With A Multimeter
A multimeter is a device that can be used to determine electrical values such as voltage, amps, and resistance. This data can help you find out if speaker wires are positive or negative. You can take the following steps to determine the polarity of your speaker wires by using a multimeter.
- Unplug the wires: The first step is unplugging the wires and preparing your workstation. This will help you have a clean slate so you can get everything plugged in correctly.
- Connect to a 9-volt battery: Next, you want to connect the wires to a 9-volt battery.
- Set multimeter: You want to set your multimeter to the DC voltage setting by rotating the knob on the center of the multimeter.
- Connect multimeter: Once the correct settings are in place, you can connect the wires to the multimeter.
- Check the reading: Finally, you will get a reading on the multimeter that is either negative or positive for each connected wire. This is how you determine the polarity for each wire.
Once you have taken these steps, you will know which speaker wire is negative and which one is positive.
The multimeter I have is the Neoteck NT8233D Pro (link to check the price on Amazon), but there are plenty of options on the market.
Visual Or Physical Clues To Distinguish Your Wires
If you are looking at speaker wires and trying to tell them apart, there are usually some physical clues you can look for to distinguish the difference.
- Connection points: Take a visual inspection of the connection points on the back of the speakers. There may be some connection differences that can help you determine which wire fits in which place. Considering the connection points can help you see the subtle visual differences between the two wires.
- Look for a stripe: Some speakers may have one wire with a stripe on it. A stripe on a wire usually indicates that it is negative.
- Physical differences: Some wires may also have some distinguishing physical differences. In some cases, one wire may be smooth, and the other may have tiny ridges or bumps on it. This can help you tell them apart and line your wires up correctly.
If you look for visual or physical differences, you should be able to determine some differences between the two wires. This will help you figure out which one is positive and which is negative.
The Importance Of Matching Wire Polarity Correctly
Fortunately, connecting speaker wires in opposite polarity will not damage the speaker or the amplifier (assuming the connections are made properly). However, swapping the positive and negative speaker wires at the speaker or amplifier end will consequently alter the speaker's polarity within the system.
Put simply, reversing the positive and negative speaker wires will cause the speaker to push when it's supposed to pull and vice versa.
If there's only one speaker in a system, the effect of mixing up the speaker wires will be minimal and imperceivable.
The issues happen when multiple speakers are used, like in a stereo system, and one or more speakers are in reverse polarity to the other speakers.
For this explanation, let's keep things simple by considering two speakers and a single mono audio signal. One speaker is wired correctly, and the other is wired in opposite polarity. Both speakers are producing the same sound level.
The sound waves from one speaker will be in opposite polarity to the sound waves from the other speaker. In other words, the two sound waves will be 180º out-of-phase.
This causes destructive interference where the positive change in sound pressure of one sound wave cancels out the negative change in sound pressure of the other wave. The positive amplitude of one wave cancels out the equal but opposite amplitude of the other.
This is particularly noticeable at lower frequencies because the wavelengths are longer and less affected by the physical space/medium the sound waves propagate through.
So misidentifying the positive and negative wires of a speaker cable can have detrimental effects on the speaker system's sound, particularly in the low-end.
Of course, miswiring speakers can potentially damage the speaker, amplifier, cable and more. We're assuming that all connections and wires are made properly other than the simple switching of the positive and negative speaker wires.
Related article: Why Do Speakers Need Amplifiers? (And How To Match Them).
How Is Speaker Wire Polarity Determined?
The actual polarity of the signal in a given speaker wire polarity is largely determined by the amplifier driving the speaker.
A wire without any signal passing through it is simply a conductor (generally made of copper). It's the signal running through the wire that will be subject to polarity.
The “positive wire” connects the amplifier's positive output terminal to the speaker's positive input terminal. The “negative wire,” conversely, connects the amplifier's negative output terminal to the speaker's negative input terminal.
How Do You Know The Wires Are Properly Installed?
You can check for the following signs to ensure that your speaker wires are correctly installed.
- Colour-coding: Speaker wires are often colour-coded, which will help you remember which one is positive and which one is negative. The most common colour coding is red and black, where red is positive and black is negative.
- Listen: When you are using your speakers, how is the sound quality? If you notice sound disruptions, interference, or varying volumes, the chances are good that the wires may be mixed up.
- Manual: Look over the manual for your speakers to ensure that you install the wires correctly.
- Physical or visual differences: Look for physical or visual differences between the two wires. These varying differences can help you tell the wires apart so you can hook them up correctly.
- Tests: You can test your speaker wire polarity using a multimeter or a 9-volt battery test. Both of these tests can give you a definitive answer about which wire is negative and which one is positive.
If you look through all of these factors, you will be able to ensure that your speaker wires were installed correctly. This will provide you with the best listening experience so you can have good quality audio whenever you need or want it.
What is the difference between sound and audio? The key difference between sound and audio is their form of energy. Sound is mechanical wave energy (longitudinal sound waves) that propagate through a medium causing variations in pressure within the medium. Audio is made of electrical energy (analog or digital signals) that represent sound electrically.
Related article: What Is The Difference Between Sound And Audio?
What is microphone polarity, and how does it affect audio signals? Microphone polarity is thought of and noted in two ways. The first compares the movement of the diaphragm to the direction (positive or negative) of the outputted audio signal (AC voltage). The other tells us which pin (2 or 3) of the balanced output carries the positive signal versus the negative.
Related article: Microphone Polarity & Phase: How They Affect Mic Signals
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