What Happens if You Reverse Speaker Wires? [Speaker Polarity]

Have you been wondering if speaker cables with correct speaker wire polarity sound better than speaker cables of inverted speaker wires? Though relatively common, speaker polarity is a frequently misunderstood topic.

But before anything, it’s important to understand why polarity matters when it comes to your speakers. Naturally, these devices are of two different kinds, those with positive and those with negative polarities. Your speaker’s polarity determines whether the sound moves forward or backward.

In short, speakers with a negative pole will have the air moving towards their intended audience, while those with a positive pole push the air away from their intended audience. 

When connecting wires between the speaker and amplifier, the rule of the game is to join the positive amplifier terminal to the positive speaker terminal. However, this is not always the case as most car stereos installed by amateurs tend to have the red and black wires reversed.

What Happens if You Reverse Speaker Wires

Reversing your speaker wires results in the speakers moving inwards when they push outwards and vice versa. Depending on several factors, such as how many speakers are in use, this can result in dire consequences.

You will hardly notice any difference when you reverse wires in a system containing only one speaker. The impact will, however, be more felt in a situation where multiple speakers are in use. Reverse polarity in such a situation can result in the following.

The Amp Might Blow Up

If the red and black wires are connected to the wrong terminals on your amp, it may blow up. Here’s the reason – The amplifier expects voltage from one wire and some current from the other wire. If both wires supply voltage (or in the case of a short circuit, neither wire does), the amp will most likely fry.

This is a prevalent mistake when wiring an amplifier, and just because a schematic shows red to positive and black(or white) to negative doesn’t mean that’s how things are supposed to be wired. What matters is that the two wires are connected on both ends properly. Red should always go to positive, and black or white should always go to negative.

An amp that continues to run without problem after being wired up improperly has either been designed poorly or was wired incorrectly by someone who didn’t know much about safety.

Loss of Bass

The first thing you will notice when your speakers are out of phase is the loss of bass from the The first thing you will notice when your speakers are out of phase is the loss of bass from the affected speaker. Remember, air pressurization by the speaker’s diaphragm generates the bass tones; therefore, interfering with the speaker wires make the speakers work in opposite directions hence losing the bass.

Besides this reversing your speaker wires will result in the drums becoming inaudible and the music losing its masculinity.

Poor Quality Sound

Low sound quality is another issue that arises from reversed speaker wires.

The system will not do a good job from the moment you turn it on. In most reversed speaker wire cases, the sound from one of your channels is likely to sound noisy and may also have a pop effect.

You may also hear your voice echoed back at you, especially when listening through headphones.

Car Speaker Polarity

Speakers work best when polarity is preserved, i.e., kept the same. If you connect the positive and negative leads from your car stereo backward, you’ll probably blow the speakers, but there is nothing to worry about as most speakers have a built-in protection circuit that will keep them safe if this happens.

Car speaker sound is naturally meant to be directional, with bass frequencies coming out of the car door and midrange/high pitches coming from the car’s dashboard. Therefore every time you flip your car, speaker connections around you will change how the music sounds.

How To Test Positive and Negative Wires Without a Multimeter

Knowing which of your speaker’s wires is positive and which one is negative will help you wire them correctly and prevent potential damage from reversed polarity. Below are some of the methods you can use to test your wire’s positivity and negativity without a multimeter.

  • Read the manual. You can get a clue from the manual, especially where the wires will mostly be color-coded. The unique color code tells you where each wire goes.
  • Alternatively, you can tell which wire is positive and which is negative by looking at the transparent casing. The copper wire will always be the positive one, while the silver strand will always carry the negative charges.
  • You can also use a 9-Volt Battery test to help you determine which wire is positive and which one is negative.
  • Lastly, you can examine your wire’s physical features to determine which one is negative and positive. Some of the elements to look at are the connection points at the back of your speakers, a stripe to indicate a negative wire, and tiny bumps or smoothness on the cables to help you set them apart.

How To Check Polarity With a Multimeter

A multimeter is a device that comes with two probes, black and red, that help measure voltage and resistance. Using this data, you can quickly tell positive or negative wires apart. Some multimeters will beep when a solid connection is established with another device through a wire or terminal.

When unsure of which wire is positive and which one is negative, it’s always recommendable to use a digital multimeter in measuring the polarity as an analog multimeter can easily blow up in the event of a wrong connection.

You can use this device to check the polarity of your wires through the following steps.

Step 1: Switch on your digital multimeter and put it on the direct current voltage setting, i.e., the symbol on your device that resembles a capital V.

To do this, you need to rotate the selector switch at the center of your multimeter to the said symbol.

Step 2: Connect the wires to the multimeter.

This entails attaching the leads to each wire. But before this, you should plug your multimeter’s black lead into the port labeled COM, and the red lead should be inside the port with the volt symbol.

Step 3: Check the reading on the multimeter screen

Upon attaching the leads to the wires, a figure will show up on the multimeter screen. This represents the voltage of your wire, and it can either be a positive number or a negative one.

Step 4: Interpretation of the results

The figure that shows up on your multimeter screen tells whether the connection is made correctly or not. Furthermore, you can use it to tell which wire is positive and which one is negative.

A positive figure or reading indicates that the connection is made correctly. In this case, the wire plugged into the red lead is positive, while that plugged into the black lead is negative. Be on the lookout for those tests that give you a negative reading as this indicates reversed connection which means the leads are hooked wrongly.

You, therefore, need to switch up the leads to their correct position, which a positive reading will indicate on the multimeter screen.

How To Tell if You Have Wired the Speakers Correctly

Step 1: Remove the wire from the speaker, and check if it’s marked + or +/-

Step 2: With the speaker turned on, touch one of the wires to your finger. Do you hear a high pitch tone? If not, then the speaker is wired correctly. If you hear a high pitch tone, it is not wired correctly, and your speaker will be blown out.

Step 3: Some speakers are screwed into speaker wire that has already been connected to the car. Touch one of the speaker wires to the speaker again and listen for the same result above; if none, the speaker is wired correctly.

If you hear a high pitch tone, the speaker is wired wrong and needs to be replaced or rewired by an expert.

Step 4: Turn on the radio with no music playing. You should have static coming through speakers. If you don’t, then there is something wrong with your wiring (perhaps a grounding issue) because power isn’t reaching the speaker at all, so the speaker won’t work even if it’s correctly wired.

The Final Word

Even though differentiating the right channel from the left channel may not always be easy, it’s wise Even though differentiating the right channel from the left channel may not always be easy, it’s wise to always get some guidance from your amp or receiver as these channels are most likely printed here.

Consequently, always ensure all the connections at either end of each speaker are firmly seated and any mounting brackets are fastened securely before doing the plugging. For better results, ensure to place each speaker above or below a corner seat to maximize sound quality while minimizing vibration feedback.

While at it, be careful not to place the speakers too close together as this will lead to one speaker overpowering the other or, in simple terms, loss of volume and stereo separation.

Avatar for Jamie K. Martin

Jamie K. Martin holds a degree in Audio engineering from Husson University, Bangor. Martin spends most of his time testing and trying the technology he writes about to ensure that he provides first-hand information to our customers from all walks of life.

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