We all enjoy music and speakers make that possible – but it can be confusing if you’re unsure of how exactly to connect them. Here’s a great speaker wiring diagram and informational guide I’ve put together to help you. I’ll also go into detail about why it matters how you connect your speakers below. First, here’s a basic speaker wiring diagram:
Speaker wiring diagram (click to enlarge) or click here for the Adobe .pdf version
The important things to know for basic speaker wiring and speaker use
1. Speaker impedance (the speaker “Ohms” rating)
Speakers, much like other electromechanical devices, all have an electrical resistance to the flow of electrical current, much like a standard resistor, a light bulb, or many common items you’re familiar with. The difference is how they behave when music is present when they are connected to a musical amplifier of some sort. The resistance value comes from a long coil of wire inside each speaker, called a voice coil, which makes the speaker cone move when electrical voltage is applied from an amplifier.
Speakers contain a long wound loop of wire called a voice coil. Loops of wire have a property called inductance which affects a speaker’s resistance value depending on the frequency (sound range) being played.
Because they have electrical properties that include inductance and capacitance, their “total resistance” can actually change with the music slightly. Because of this, there’s some additional complex math needed to figure out the total resistance, which in this case is called impedance. Speaker impedance is just a more sophisticated way of finding the total resistance, and by tradition is measured with units called “Ohms.” The good news is that you don’t have to worry too much about the details – it doesn’t matter for basic speaker use, and long as you observe the basic rules you’ll be fine!
2. Radios, stereos, and amplifiers have minimum speaker impedance ratings that they can handle
All amplifiers of any type – where it’s a car stereo amplifier, home stereo receiver, home theater amplifier, and so on, have a minimum Ohms (impedance) rating that must be respected. This is because as the impedance is lowered, the electrical current increases, and therefore the stereo has to do more work and will increase the amount of stress and heat it has to handle.
If your stereo is labeled by the manufacturer as being “8 ohm speaker compatible” or similar, that means connecting lower impedance speakers can cause excessive heat and possible damage very quickly. For example, connecting a 4 ohm speaker to an amplifier which specified a minimum of 8 would mean it would have to produce double the electrical current to the speaker!
Image of the rear of a home stereo receiver/amplifier. Note the recommended speaker impedance ratings shown above the speaker wire connection posts.
Also, attempting to wire 2 of these 8 ohm speakers in parallel to an 8 ohm stereo would have the same effect.
I’ve seen many attempts by people who had friends who claimed they could “boost the power” or “get more power” by some claimed trick, but it doesn’t work – and they ended up with a destroyed amplifier. An amplifier can only handle so much heat and stress before it fails, so be sure to observe these rules. Be sure you wire speakers to meet the minimum Ohm rating you need.
3. Understanding speaker wiring “polarity” – wiring the positive and negative connections
Speakers are different than other devices in that they operate using alternating current (AC) rather than direct current (DC). This is good news! It means you can’t harm your speakers in most cases by having the positive (“+”) and negative (“-“) wiring reversed. Unfortunately, it gets a little more complicated when we use more than 1 speaker.
Speaker polarity and why speakers should be wired the same as each other
As I mentioned, speakers operate by moving a cone, and they actually move back and forth in order to produce sound. When doing so, of course sound waves are produced, but if you wire 2 speakers in a stereo with different polarities (for example, one has positive and negative wired as labeled, and the 2nd speaker has the opposite) an interesting thing occurs: they are out of phase and some sound cancels out. The end result is a strange and poor sounding stereo. In most cases you will notice a huge lack of bass sound and it won’t sound pleasing to the ear as expected.
When speakers are wired the opposite of each other sound waves cancel out. When wired the same, sound waves add together for more sound.
Speakers that are wired differently sound poor because much of the sound is canceled out. Basically, it’s simply because sound waves from one speaker are moving in the opposite direction of the other speaker – and if they’re close to the same time and frequency range, often they cancel out.
This is why when 2 woofers are placed in a box and are wired in parallel but with opposite connections to each other, they are “out of phase” and have almost no bass! It is because they are doing the opposite work rather than working together to produce more sound. While one is moving up, the other is moving the opposite direction, and so on.
So the the most important thing here to remember is: wire speakers consistently the same way as each other.
4. 2-way and 3-way speakers cannot be wired in series like separate speakers
2-way speakers, such as home stereo or car audio component speakers, are those which come as a pre-designed speaker set and use a crossover. The job of a crossover (also called a passive crossover, because it use basic capacitors and inductors rather than powered electronics) is to limit the music production each speaker is best suited for.
For example, tweeters cannot reproduce bass frequencies (and can in face be damaged by them) therefore a well-designed 2-way speaker prevents this. Similarly, a woofer cannot produce high pitch sounds well and is prevented from doing so.
Unlike standard separate speakers, 2-way and 3-way speakers that have a crossover can only be used in parallel and not in series. This is because unlike separate speakers with no crossovers in this case many sounds will be filtered out. This means that little to no sound would be produced if another 2-way speaker was connected in series.
Therefore if you have a home stereo or car stereo in which 2-way speakers are used, you’ll have to add more 2-way speakers (if the total impedance can be supported by the amplifier) or add more amplifier channels for more sound.
5. Doubling the number of speakers or amount of power does not double the volume
In some cases additional speakers can be added to increase the amount of volume you can achieve or to place speakers in additional rooms, additional locations in your vehicle, and so on. You also may have wondered what would happen if you bought an amplifier with twice the power of your present one.
There’s one important thing to understand, however: having 2 or 3 speakers instead of one does not double or triple the sound. It increases a few decibels for each speaker added. Doubling the power does not double the volume either.
This is because of how the human ear works and the physics of sound. Also how speakers work and how much volume they can produce for a given amount of power.
Generally speaking, the human ear will hear a very small amount of volume increase for each double of acoustic power: approximately 3 decibels (dB) which is for most people the small amount of volume increase you notice when turning up a volume knob 1 notch.
In fact, adding more speakers will do the same as well, but will of course require additional power to drive it, too.
Example volume produced by a typical speaker for given amounts of power:
- 1W = 89 dB
- 2W = 92 dB
- 4W = 95 dB
- 8W = 98 dB
- 16W = 101 dB
- 32W = 104 dB
- 64W = 107 dB
- 128W = 110 dB
So as you can see, doubling the amount of power you can drive a speaker at does not mean you’ll double the volume.
The best ways to get more volume are:
- Use more efficient speakers (speakers that produce a higher dB volume at 1W of power – higher is better)
- Add more speakers if you have an amplifier that can support it
- Use higher-power rated speakers and a higher power amplifier if high volume is your goal
For most people an average and good stereo amplifier can produce sufficient volume to fill a room or vehicle and turn up the volume from time to time. I like to use 50W or higher per channel as a good rule of thumb when buying an amplifier.
A quick note on speaker positive and negative labels (+ and -)
Home stereo and car speakers normally often use a red or plus sign “+” to indicate the polarity for the speaker wiring terminals you need to use when connecting wire.
The following tips may be useful also:
- In some cases, as black dot or a red or black stripe is used to mark the positive terminal
- If a speaker has terminals of 2 different sizes, the larger of the 2 is normally the positive one
- For speakers with wire already attached, typically the brass or golden-colored wire is the positive one
- For speakers with wire attached but same colored wires, most have some small printing on the positive wire – be sure to check closely
Here I’ve provided you with a speaker diagram showing basic connections, I explained several important things you need to know about speakers and speaker wiring. And I’ve hopefully given you more understanding about what you need to know when it comes to connecting speakers and get the most enjoyment out of your system.
This was intended as a basic speaker wiring diagram and fundamental speaker knowledge guide, so I’ve reserved more advanced topics for another time.
Please feel free to let me know if there’s anything you feel is lacking, any questions you might have, or if you need additional guidance! I’d love to hear from you.