Headphones Specifications Explained — What Does it All Mean?

What do the specifications of headphones mean? How do I know what to look for? We’ve all been there before. You go to the store or online looking for a new set of headphones. There are so many types and styles to browse, with mind numbing levels of technical information listed. You finally find the pair that you think are perfect. When you get them home you tear through the wrapping like a five year old on Christmas morning, eager to listen to your favorite tunes in the new headphones, and plug them in. As you crank the volume up towards max, your heart sinks as the music quietly whispers to your ears. What happened? Why can’t I hear anything? Are they faulty?

Chances are that the headphones are fine. They just aren’t matched up well with the device you plugged them in to. Matched up? What do you mean? There’s a problem with the Bluetooth pairing? No, no nothing like that. There’s a lot of technology that goes into the headphones we place on or in our ears these days. Knowing what to look for will go a long way toward vastly improving your listening experience and saving you from the heartache and wasted time of having to return them. It’s also important to know that shopping merely based off of all of these “numbers” and “measurements” isn’t always wise.

What are the specifications of headphones?

If you were interested in learning about types of headphones (such as ‘operating principle’ or ‘design’ a la closed-back or open-back, etc.) you can read that respective guide, since this particular article will focus more on those terms that ‘measure’ headphones usually on boxes or at the bottom of websites they’re being sold on. With that being said, these words can be important, and there are several ‘techie terms of headphone specifications’ that we are going to want to get comfortable with to help us on this journey, and some are more important than others. Here’s our list alongside links to jump to the certain term in case you have a particular spec in mind. Otherwise, feel free to read on as you please.

• Drivers
• Transducer Technology
• Frequency Response
• Impedance
• Sensitivity
• Total Harmonic Distortion
• Sound Pressure Level
• Maximum Input Power
• Noise Attenuation

Now, I know what you’re thinking. This is way too much, I just want to know which one of these terms I need to look for, so my music sounds good? Well, if you’re looking for really solid quality headphones, there isn’t just one of these headphone specifications you should be familiar with. Knowing what these terms mean, will supply you with the tools you’ll need to make sure you’re getting truly high quality sound for your device. So, let’s unwrap some of these mysteries.

The different headphone specifications explained

Drivers

What is a driver? Simply put, the driver of headphones is just a magnet, some voice coils and a diaphragm that takes the electrical signal from your device and turns it into sound that your ears can pick up. They come in different sizes and styles. Typically, larger drivers mean more power can be pushed through them, but don’t get caught up on size. While the larger drivers will give you better bass at low frequencies, the sound will start to break down at the higher frequencies. Think of it like the large, subwoofer like speakers in your car or home theater. They have huge drivers and do great with explosions or 808 drums but when you hear voices or violins, the sound is muffled or distorted. This is because the actual surface of the diaphragm will change shape when high frequency sound passes through it, and with large drivers the frequency response (which we will discuss later) will become irregular, and cause distortion. Smaller drivers can also create very good levels of bass, with some as small as 6mm producing deep bass without distorting the higher frequency sounds. Drivers come in different types, there are balanced armature, electrostatic, planar magnetic and dynamic.

Without wading too far from the beach, dynamic is the most common type. These are most commonly found in your standard over-ear or on-ear headphones. Dynamic is big, but not subtle when it comes to sound. Balanced armature is usually what you’ll find in earbuds or in-ear headphones. They’re very tiny, so they can fit more than one into the earbud, which are combined to create very good sound quality. Electrostatic drivers are the old reliable home loudspeaker style. Nowadays they’ve been able to miniaturize them into earbuds, and offer low distortion and relatively clear sound. Last but not least is planar magnetic (orthodynamic). This type of driver is known as a bit of hybrid between dynamic and electrostatic drivers.

Transducer Technology

Headphone specifications vary from brand to brand, and the transducer is not really one of those items that you need to be an expert on to be able to buy a good set of headphones. All the transducer does for you is take the electrical signal that your CD or phone will create, and convert it into a soundwave that your ears can pick up.

Frequency Response

Frequency response is one of those techie terms of headphone specifications that you’ll want to familiarize yourself with. The frequency response is the range at which your headphones can produce sound. They run the spectrum from high frequency treble (30,000Hz), to low-frequency bass (5Hz). Basically, the bass, treble and mid-range sound you hear in your headphones is like the speaker system in your car. You have big speakers for the bass, medium size speakers for the mid-range sound and smaller speakers for the treble. In headphones, they are typically all combined into one speaker.

Generally speaking, the range is from about 5Hz to as high as 40,000Hz, although most headphones try to stay in the 20 to 20,000Hz range. Noises above 20,000Hz are not always detectable to some humans and with noises below about 18Hz, your eardrums don’t really hear sound as much as they feel it. Because not all companies label their speakers the same, you’ll see things like “dB” plus/minus. Don’t worry, all this means is how far the sound differs from a perfect, accurate reproduction of the original recording through the entire frequency range. This is also sometimes referred to as “flat” sound. The closer the number is to zero, the closer the headphones are able to reproduce the original accurately.

Impedance

When it comes to the specifications of headphones, impedance is another one of those techie terms you’re going to want to be familiar with when purchasing a new set. When companies list this rating, you see it as the Greek letter for omega and referred to as “ohms”. Simply put, this rating is expressed as a range from about 2ohms to over 600ohms, which basically represents how high you have to turn the volume up to get a decent listening level. The higher the ohm number, the more power your device needs to reach that level. In the old days, home stereo systems could only dish out enough power to push 4 to 8ohm speakers, and were stupidly expensive. Today you can find high impedance headphones for a fraction of the costs of yesteryear. Many higher impedance headphones however will call for a headphone amplifier in order to fully power them up.

Sensitivity

Sensitivity is another one of those techie terms of headphone specifications that you’ll want to know about. In a nutshell, it’s all about efficiency. How efficient are the headphones at converting that electrical signal from your CD or phone into an undistorted soundwave. The sensitivity rating is listed as a decibel level (dB), and most headphones range from about 85 to 105dB. Anything above 110dB can damage human ears in a short amount of time, which is something to consider when that sound source is less than an inch from your ear.

Low sensitivity headphones need more power from the device to give you high quality sound, but in exchange for that, they will last longer than their high sensitivity counterparts. High sensitivity headphones offer better performance with less power, but as you turn the volume up toward max distortion becomes a factor, and the headphones (and your ears) may be damaged over time.

Total Harmonic Distortion (THD)

Another term that you don’t need to be an expert on is total harmonic distortion, or THD. Your device and your headphones have different levels of THD, and may actually measure them differently too. THD refers to the comparison of the signals from the input and output of your devices and is represented as a percentage. The actual percentage is measured from a baseline test with zero being perfect. In terms of headphone specifications, total harmonic distortion is barely noticeable by the human ear, especially when you consider most headphones have a rating of 0.1 to 0.005 percent. Even with noise cancelling headphones, you still get some sound from the outside world. For total harmonic distortion, lower is better. Look to get as close to zero as possible.

Sound Pressure Level (SPL)

Sound pressure level is kind of married to the sensitivity level that we discussed before, so we won’t spend too much time on it here. While sensitivity is all about efficiency, the sound pressure level measurement (or SPL) is all about the maximum dB level that those headphones will output. When you see this rating, it will be shown as dB SPL/mW, or dB/mW and most headphones and earbuds these days will be between 85 and 125 dB SPL/mW range.

Maximum Input Power

Now that our heads are spinning from all of this complicated information, now we’re going to start combining these headphone specifications together, to help you better understand maximum input power’s importance when looking for new headphones. This value of maximum input power refers to how large of a power supply the headphones can support, and is indicated in kilowatts (or mW). Some companies don’t list maximum input power on their headphone packaging or spec sheets, but you should be able to find that information on the company’s website. The user manual of your source (cellphone, amplifier, TV etc.) should also give you that information. This is a kind of match up situation when buying new headphones. Most cellphones produce about 1 watt (0.001mW), a headphone amplifier can push that number up to as high as 3 watts (0.003mW). 3 watts is a lot of power, and can easily damage the headphones if not matched properly. Ideally, you will want to find headphones that have a maximum input power close to your source.

Noise Attenuation

Noise attenuation is defined as the loss of energy from sound waves. As sound waves travel through space, and come into contact with other materials along the way, it loses its’ energy. For headphones, what we are talking about is the construction materials used for noise cancelling and absorption of outside sound in the headphone itself. For the most part, this particular bit of information is not very useful, and trying to find out what sound dampening materials companies use can be an exercise in futility. Foam and cotton are the most common, however some companies use acoustic fiberglass for their sound insulation.

What do the specs of headphones mean?

Headphone specifications are complex and have several different components that go into creating that perfect sound for your tunes. Hopefully we’ve cleared up some of the technical mumbo jumbo, and you can now go out into the world confident in finding that perfect set of headphones for home and travel. Let us know in the comments if you know of any other important specs to keep in mind and we’ll update this article accordingly!