What does ohm and impedance mean in headphones?

What does ohm and impedance mean in headphones?

When buying a new pair of headphones, what is the one thing you look for?

Let’s be honest, its sound quality (you’ll probably be ready to spend a few extra bucks or get a lesser-known brand’s headphones if it means you get better sound quality).

While there are many different factors that play major roles in the sound department, one such factor is impedance or ohm.

So, what does ohm and impedance mean in headphones?

Let’s talk some science, eh?

Impedance is the resistance of an audio device to the flow of electrical signals. The unit in which it is measured is the ohm.

Too much science? Let’s make it simpler for you!

What does ohm and impedance mean in headphones?

Every conductor has some resistance to electricity. When electricity flows through a wire, there’s a certain level of resistance that acts as a barrier in the path of the electric current. Ohm is the unit used for resistance measurement.

Headphones too have some level of resistance in their drivers, termed impedance. Since it is a form of resistance, it is also measured in ohm.

What is the role of impedance in headphones?

80ohm headphone
Source: hhgregg

Headphones’ impedance range from 8 to 600 ohms.

Based on the level of impedance, headphones are divided into two categories:

Headphones with <25ohms impedance (known as “low impedance headphones”) and Headphones with >25ohms impedance (known as “high impedance headphones”).

Let’s talk more science, please? We promise to keep it simple!

A dynamic headphone driver (most headphones use this type of driver) has a component called a voice coil. The coil is basically a wire that’s wound around the driver (thinner wire, more windings). On receiving the signal through the coil, an electromagnetic field is formed, thus, magnetizing the coil which in turn causes vertical movement that’s determined by the frequency (which then causes the movement of the diaphragm and thus we receive the audio signal).

What’s important here is the voice coil. The coil’s length, size, material, and the number of turns affect the sound quality produced.

To sum up: Thinner the wire, stronger the electromagnetic field, and higher the impedance.

This impedance affects the sound quality in terms of bass, soundstage, intensity, and loudness.

Higher impedance means clearer sound, better bass response, lesser distortion, better soundstage- overall better audio quality.

However, higher impedance requires greater power to drive the audio gear so it’s difficult to pair them with small, portable audio devices.

It means low impedance headphones (<25ohms) can be paired with battery-powered devices (generally used with smartphones or laptops) whereas the high impedance headphones (>25ohms) require an external amplifier to function properly(studio/professional level headphones).

Although, some headphones with impedance between 20 to 40ohms produce decent sound quality without an external amp.

Here’s a video explanation of impedance in headphones:

What level of impedance is right for you?

The low impedance headphones are generally paired with smartphones so for casual listening purposes, 25ohms is good enough. Since it requires very less power, it works perfectly fine with battery-led phones, laptops, or even computers.

For audiophiles or professional/studio purposes, you may go as high as 30ohms or more for the best listening experience.

Basically, if you have the budget to invest in a pair of high impedance headphones, no one’s stopping you but you’ll also need to invest in an external amplifier. Otherwise, low impedance does the magic (there are also other factors that play big roles in the audio quality so you don’t really need to get high impedance).

Plugging the right device into the right headphones

Make sure to plug the headphones into a suitable device. If you do otherwise, the audio quality will be drastically affected or even some severe damage may occur to the devices.

For example, if you connect high impedance headphones to your phone or laptop, it won’t offer the performance it is capable of, i.e., it won’t give you the audio quality you expect. The volume might be too low and you’ll constantly need to keep the volume high, which in turn affects not only your device but your health as well.

Conversely, if you connect low impedance headphones to an amp, you’ll get terrible audio quality and may even end up damaging your device.

Therefore, if your sole purpose is casual listening, do not waste your money on high impedance headphones. You can get a pair of low impedance headphones and get decent audio output. Leave the high impedance headphones to the professionals, eh?

Suggestions

Model NameImpedanceFrequencyDescription
Audio-Technica ATH-M50x37ohms15Hz28kHzOver-ear, sonic sound; professional-grade
Beyerdynamic DT 770 PRO32ohms5Hz35kHzClosed-back, over-ear headphones; studio sound
Sennheiser HD 660 S150ohms10Hz-41kHzOpen-back, over-ear headphones; audiophile headphone category

FAQs

Why does impedance matter in headphones?

Impedance has a considerable impact on the sound quality (bass, loudness, soundstage) and, hence, it’s an important factor to consider before buying headphones.

Do low impedance headphones sound bad?

Low impedance headphones sound fine when connected to the correct device (low-powered smartphones). In comparison, high impedance headphones do have better audio quality but they won’t do any good if you connect them to the wrong device.

How much impedance do I need for my jack?

Traditional headphone jacks have an impedance range from 0.1ohms to 25ohms. Most people use 32ohms impedance headphones.

Conclusion

That’s everything you need to know about ohm and impedance in headphones. To know more about headphones, check out other articles on our website: What is the Difference between a Headset and Headphones?