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Why Do Speakers Hum When You Touch the Plug Jack or Cable?

I’ve seen my fair share of odd habits among sound engineers and musicians. But one thing that always seems to baffle me is the tendency for some speakers to hum or buzz when you touch the plug jack or cable. It’s like they’re alive and trying to communicate with us through the power of electricity!

But in all seriousness, there’s actually a scientific explanation for this phenomenon, and in this article, we’ll delve into the world of electrical currents and impedance matching to uncover the truth behind the mysterious humming of speakers. So let’s dive in!

Image of a black speaker beside a monitor. Source: marinko krsmanovic, pexels
Image of a black speaker beside a monitor. Source: Marinko Krsmanovic, Pexels

Why does the speaker hum when you touch the plug jack or cable? When you touch the plug jack or cable of a speaker in a home recording studio, it can cause the speaker to hum due to a change in the electrical current flowing through the circuit. This change in current can disrupt the delicate balance of the impedance matching between the amplifier and the speaker, causing the speaker to produce a humming sound.

Is it normal for speakers to hum?

In most cases, it is not normal for speakers to hum. Speaker hum is typically caused by a problem with the electrical circuit or the impedance matching between the amplifier and the speaker, and it can be fixed by identifying and addressing the underlying issue.

However, there are some situations where a small amount of hum is considered normal and may not be worth worrying about. For example, some amplifiers and speakers may produce a small amount of hum due to the design of the circuit, and this hum may not be noticeable unless the system is played at very high volumes.

Additionally, some speakers may produce a small amount of hum when they are first powered on, but this hum should quickly disappear once the speaker has warmed up.

Typical causes of speakers humming.

Humming speakers can be caused by a variety of different factors, but the most common culprits are interference from other electrical devices in the home studio and Electrical Ground Loops.

Electromagnetic interference

Take note that the electromagnetic frequency range from 30 Hz to 300 GHz is prone to radio frequency interference (RFI), a frequent kind of EMI. Because of electromagnetic induction, electrostatic coupling, and electrical conduction, EMI will introduce noise to an audio signal. Electric current creates magnetic fields, while magnetic fields induce a current.

Because of the aforementioned power mains, hum may be produced in both the audio wire and the speaker. Similar interference, noise, and hum in the audio conductors and, by extension, the linked speakers may be caused by adjacent and distant radio wave transmission.

Electrical ground loops

Connecting electronic components in a manner that creates several pathways to the ground is known as a ground loop. It is preferable for a pair of points in an audio circuit to have the same ground reference potential. Different ground potentials exist between these two places in a ground loop.

Suppose a mixing board and an active speaker are both connected to the ground in the correct manner. A speaker’s input is wired to the mixing board’s output. The shield of this audio cable is connected to the ground of both the speaker and the mixer, creating a closed conductive ground loop that protects the signal from electromagnetic interference and returns it to the source.

Connecting the active speaker and mixer ground wires to the power mains and the building utility ground wire complete the closed-loop system. You may find either 50 Hz or 60 Hz on the AC power mains, depending on your location. Due to the resistance of the ground conductor in the cable, a tiny alternating current (AC) voltage drop will be induced across the ground in the power mains.

The produced 50- or 60-Hz interference may be audible as humming or buzzing in the speakers since audio signals are alternating current voltages between 20 Hz and 20,000 Hz.

Mechanical failure

Finally, the speaker’s internal hardware may be at fault if there is a buzzing or humming sound. Hushing and buzzing may be caused by faulty equipment itself or by making the audio route more vulnerable to EMI and ground difficulties.

Human conduction

Our own bodies are electrical conductors. In reality, our CNS can’t successfully relay messages to and from the brain and the rest of the body without electricity. Humans’ ability to reason, take action, and see the world around them would all cease to function if they lost access to electricity.

Even though we’ve developed in electromagnetic fields, our “inner electricity” may be influenced by the magnetism and electricity of our surroundings. In terms of electrical conductivity, our skin is, thankfully, the least conductive component of our body. Because of its great natural resistance, the skin shields us from electrical impulses delivered from the outside.

Skin is not an ideal conductor of electricity because of its low moisture content and absence of sodium and potassium ions. Wetting the skin will naturally reduce the resistance. However, our bodies act as antennas, picking up electromagnetic energy from our surroundings and converting it into a voltage that can be felt on the skin.

Capacitance refers to the capacity of a material to store an electric charge, and the human body possesses this property. The electrostatic shock we experience is the result of this charge dissipating (after rubbing our feet on a carpet and then touching a doorknob, for example).

Mechanical failure

Finally, the speaker’s internal hardware may be at fault if there is a buzzing or humming sound. Hushing and buzzing may be caused by faulty equipment itself or by making the audio route more vulnerable to EMI and ground difficulties.

How to find and fix hum in 3 easy steps?

Here are three easy steps you can follow to find and fix hum in your home recording studio:

Identify the source of the hum.

The first step in fixing the hum is to determine where it’s coming from. This can often be done by unplugging each piece of equipment in your studio one by one and listening for the hum to disappear. If the hum disappears when you unplug a specific piece of equipment, then that is likely the source of the hum.

Check for ground loops.

Once you’ve identified the source of the hum, the next step is to check for ground loops. As mentioned earlier, ground loops can be a common cause of hum, and they can be caused by multiple paths for the electrical ground to flow. To check for ground loops, try using a ground loop isolator between the source of the hum and the rest of your equipment.

Image of a speakers inside a music studio. Source: andreu marqu, pexels
Image of a black speaker beside a monitor. Source: Marinko Krsmanovic, Pexels

Check the impedance matching between the amplifier and the speaker.

Another potential cause of hum is a mismatched impedance between the amplifier and the speaker. To fix this issue, you’ll need to carefully match the impedance of the amplifier and the speaker. This can often be done by consulting the manufacturer’s specifications for both the amplifier and the speaker and making sure that the impedance of the two is closely matched.

By following these three steps, you can quickly and easily find and fix hum in your home recording studio.

If you want even more tips and insights, watch this video called “How to Fix Ground Loop Noise, Hiss, Buzz, & Hum (Simple & Cheap!)” from the FireWalk YouTube channel

A video called “How to Fix Ground Loop Noise, Hiss, Buzz, & Hum (Simple & Cheap!)” from the FireWalk YouTube channel
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Frequently asked questions (FAQ)

Do you still have questions? Below are some of the most commonly asked questions about why speakers hum when you touch the plug jack or cable.

Difference between speakers and monitors.

Speakers and monitors are both types of audio playback devices, but they are designed for different purposes and have some key differences. Speakers are typically designed for general-purpose listening and are often used in home stereo systems, portable music players, and other consumer audio devices.

Monitors, on the other hand, are designed specifically for use in recording studios and other professional audio applications. They are typically designed to be more accurate and neutral than speakers, which makes them well-suited for critical listening and mixing.

Difference between speakers and an amp.

Speakers and amplifiers (typically called amps) are two different components that are typically used together in a sound system. The main difference between the two is that speakers are designed to convert electrical signals into sound waves, while amplifiers are designed to increase the strength of the electrical signals that drive the speakers.

How an audio cable can cause humming in a speaker?

When an audio cable is connected to a speaker in a home recording studio, it can cause the speaker to hum due to a change in the electrical current flowing through the circuit. This change in current can disrupt the delicate balance of the impedance matching between the amplifier and the speaker, causing the speaker to produce a humming sound.

Conclusion

In conclusion, the humming of speakers when you touch the plug jack or cable is caused by a change in the electrical current flowing through the circuit. This change can disrupt the impedance matching between the amplifier and the speaker, causing the speaker to produce a humming sound.

While it might seem like a mysterious and annoying phenomenon, the truth is that it’s just a simple case of physics at work. So the next time your speakers start humming, just remember to keep a steady hand and avoid touching the cables, and you’ll be able to enjoy your music in peace.

This article covered whether it is normal for speakers to hum, the typical causes of speaker humming, and how to find and fix it in three easy steps. Here are some key takeaways:

Key takeaways

  • In most cases, it is not normal for speakers to hum.
  • Humming speakers can be caused by a variety of different factors, but the most common culprits are interference from other electrical devices in the home studio and Electrical Ground Loops.
  • There are three easy steps you can follow to find and fix hum in your home recording studio.
  • Pc audio static Another reason I like thunderbolt and external USB ports is that they are less vulnerable to radio frequency interference.
  • You only need an isolating catv connector for this.
  • If you put an isolation transformer in line with the antenna, it should stop picking up interference.
  • There may be a problem with the microphone or the cord, or the active monitors themselves may be emitting a low-level hum.

So, does your speaker hum whenever you touch the plug jack or cable? And did I cover everything you wanted to know? Let me know in the comments section below (I read and reply to every comment). If you found this article helpful, share it with a friend, and check out my full blog for more tips and tricks on music production. Thanks for reading, and never stop making music.

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Audio Apartment Author
Written By Andrew Ash
Hey there! My name is Andrew, and I've been making music since I was a kid. I now run this blog all about home studios and music production. If you want to improve your home studio setup, this is the place for you!

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