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Are Speakers AC or DC? (We’ve Got The Answer)

Even if you’re not an audio engineer, you may be curious about speaker power. Are speakers AC or DC? Does it make a difference?

The simple answer to this question is that your speakers will always need AC power to run. However, the more complex answer to this question will largely depend on whether you’re dealing with an active or a passive speaker, as you may utilize both AC and DC to power your speakers. 

speakers ac or dc

A passive speaker driver will need an amplifier connected to a DC source as it will need this to run effectively and convert the energy from AC to DC. The amplifier is what amplifies the audio signal in your speaker.

AC drives a speaker since audio is an AC signal. Therefore, the DC power must provide a constant power source, which the amplifier can amplify the input signal. 

Since a speaker system has several parts, it can be more complex and dependent on whether the power supply is built-in or external. For example, if the power supply is built-in, the speaker can take AC directly from the wall when plugged in.

On the other hand, an external power supply is not built-in and will often need to convert the AC from the wall into DC to power your device. 

Also, read my Guide To How Speakers Share Power

Are Speakers AC or DC? What’s The Difference?

Before diving in deeper, it’s essential to understand the basics of AC and DC and the differences between the two. No, it isn’t just the name of the band on your playlist.

According to the MIT school of engineering AC and DC are different types of voltage or current used for the conduction and transmission of electrical energy. 

The differences between AC and DC come down to the flow of electrons in a current. 

DC stands for direct current and is constant and moves in one direction. Whereas AC or alternating current moves in a wave-like oscillating pattern.

The current can also change direction, so this makes the voltage in AC currents reverse periodically. 

AC has become the dominant power source because the wave-like motion of the current allows it to travel more efficiently.

In addition, AC can distribute power at lower voltages, making it ideal for transmitting electricity over long distances. As a result, homes today are wired for AC.

However, products in your home that use batteries consume DC power, and you will find DC in almost all home electronics. Furthermore, if you plan to build out any digital electronics, you will need to use DC to power them.

Therefore it’s essential to understand how to convert AC to DC if you plan to do this. 

If you plan to plug your electronics into a wall outlet, you will need to convert AC into DC using a power adapter or AC/DC adapter. 

Understanding Active VS Passive Speakers

When you purchase a speaker, they will usually come in two distinct types: active and passive. 

An active speaker is the most common type to purchase out of the box and has a built-in power supply and amplifier.

If you are buying an active speaker, you can plug it in to use the AC directly from the wall outlet.

If your speaker comes with a power cable, it’s already active. Therefore, all Bluetooth and smart home speakers will come active. 

On the other hand, passive speakers, essentially the speaker driver, won’t have a built-in power supply and won’t have a power cable.

Instead, you will find jack sockets or wire connectors on the back of your passive speakers that you will need to connect to an amplifier to make it work.

Passive speakers will not come with an amplifier built into them as an active speaker will have.

Speakers do require a certain amount of power to make them function. It will be up to you to determine what amplifier will best fit your needs. 

AC and DC have an Interesting History

Interestingly enough, there is a history of rivalry between the two currents. In the late 1800s, Thomas Edison had many patents that made it in his best interest to promote DC.

Eventually, George Westinghouse purchased patents using AC motors, and the rivalry began between the two. 

Edison ran a smear campaign to discourage AC in the United States and prove that DC was the ideal way to transmit and distribute power.

He even lobbied state legislatures to block it. He even went so far as to have animals electrocuted publicly to show that AC was more dangerous than DC. 

His plan worked for a while until AC eventually proved to be the more efficient source for powering lights and motors and providing more rural communities. Thus the rise of AC began. 

Frequently Asked Questions Regarding The Topic (FAQs)

How Do Speakers Work?

Although significant advances in speaker design have come about, the fundamentals of speaker design haven’t changed in close to 100 years. 

The round piece of the speaker that many people think is the speaker is the speaker driver. The speaker driver is what you will find mounted in the speaker box. The speaker driver is the electroacoustic component that makes a loudspeaker work.

This transducer transforms energy from one form to another. In this case, it converts the amplified electrical waves from your device to sound pressure waves that we hear. 

It does this because the amplifier feeds a signal into two terminals in the back of the speaker. The terminals pass the current into a cylindrical coil of wire attached to a permanent magnet at the base of a cone.

The coil then moves back and forth in the magnetic field, causing the speaker cone to move. This movement and vibration cause pressure variations in the air that produce the sound waves we hear. 

Why is Impedance Matching Important For My Speakers?

If you plan to wire your home theater, it’s crucial to take into consideration your impedance. You will need to make sure the amplifier you’re using matches up with your speaker’s impedance. 

To do this, you’ll need to check the speaker manual or the back of your speaker for the speaker impedance in ohms.

You can then check your amplifier for the corresponding impedance information. 

If you cannot match them up exactly, play it safe by plugging your speakers into a higher impedance port. Doing this will prevent you from overloading your amplifier and potentially blowing out your speaker. 

It’s also a good idea to stick with the wires that came with your speaker instead of wasting your money on overpriced speaker cables. 

Why Is Power Important To Consider When Matching My Amplifier To My Speaker?

Like the impedance, your amplifier power must be a good match for your speaker. Again, check the manual for the maximum power rating in watts. 

To be on the safe side, it’s a good idea to purchase an amplifier with a lower power rating than your speaker, so you won’t risk blowing your speakers out at maximum volume. 

Take into account the size of the room that you’re looking to set your equipment up in. You might be surprised to learn that more watts aren’t always the answer if you set up in a smaller room. 

Sources

  1. https://www.answers.com/Q/Is_a_speaker_usually_driven_with_AC_or_DC_current
  2. https://engineering.mit.edu/engage/ask-an-engineer/whats-the-difference-between-ac-and-dc/#:~:text=DC%20is%20constant%20and%20moves,like%20pattern%2C%E2%80%9D%20says%20Berggren
  3. https://learn.sparkfun.com/tutorials/alternating-current-ac-vs-direct-current-dc/all
  4. https://www.soundguys.com/power-speakers-30171/
  5. https://www.bbc.co.uk/bitesize/guides/zpnc2nb/revision/9#:~:text=Alternating%20current%20supplied%20to%20the,which%20pushes%20the%20cone%20outwards.&text=The%20direction%20of%20the%20magnetic%20field%20around%20the%20coil%20reverses
  6. https://www.youtube.com/watch?v=_nnxXqZsb9I
  7. https://www.audioholics.com/audio-amplifier/impedance-selector-switch-1/amplifier-and-power-supply-basics#:~:text=Amplifiers%20require%20a%20DC%20(sometimes,to%20amplify%20the%20input%20signal
  8. https://www.dummies.com/consumer-electronics/home-theater/understanding-how-speaker-drivers-work/
  9. https://www.youtube.com/watch?v=xi_5Moyyens