Technical specifications for headphones: everything you need to know.
Headphones are seemingly simple pieces of equipment. You put them on, press play and enjoy. However, like everything in life, the devil is in the details… And if you want to get the best out of them or make the best purchase, it doesn't hurt to know a little about how they work. It's important that you have some basic notions.
Did you know that if you spend a lot of money on high-end headphones, maybe you should take advantage of that and connect them to a headphone amplifier, to get the most out of them? What are drivers and what are they for? Did you know that knowing the technical specifications of your headphones can help you avoid breaking them on the first week? How many people have had to retire their headphones prematurely because they pushed them to the limit without knowing how much power they could give!
But we don't want to give you the lecture of the century. For that you will already have other people. We are aware that some of you may find this technical stuff both boring and frustrating. That's why we've put together a comprehensive but very simple guide to the basic terms and specifications of headphones that you should know.
What is an audio driver?
This concept is basic. When manufacturers talk about headphone drivers, they are referring to the part of the headphones that generates the sound. These are usually small, thin, disc-shaped devices located inside the ear cups of the headset. A headphone driver is powered by the electric current that travels from the source through the cable, and then launches it into our ears as sound.
If all goes well, you will never have to see a driver, unless you get curious and disassemble the headphones. All we need to know is that the headphone drivers are the ones that provide the sound, and depending on the type and size of the driver, they will sound different.
Let's first talk about the size of the driver. They are usually measured in millimeters. The size of headphone drivers can vary from 6-12mm in in-ear headphones, and up to 40-100mm in large headphones, such as HiFi headphones or gaming headsets.
Many people think that the larger the drivers in headphones, the better the sound. And this is not always the case. It's true that the bass can sound cleaner. However, larger drivers tend to have more difficulty in reproducing high frequencies (such as those of violins).
Therefore, although the size of the headphone driver helps us to get a slight idea of how they will sound, there are many other indicators that are just as important: types of drivers, impedance, sensitivity, power…
What types of music headphone drivers are in the best headphones?
The most common types of dynamic audio drivers. We find this headphone diaphragm unit in almost all on-ear and many over-ear headphones. They are capable of producing good quality bass, but the level of detail in the other frequencies can fall short. They are susceptible to distortion, especially at high volume levels.
Flat magnetic driver
Also called Orthodynamics. These types of audio drivers are mostly found in open over-ear headphones and are usually expensive. With the flat magnetic headphone drivers, high sound fidelity can be achieved by producing clear and defined tones. They are often used in home headsets, as they are heavy and less portable than dynamic drivers. The sound quality is excellent and they do not cause any distortion.
Balanced armature drivers
They are smaller than dynamic drivers and are usually found exclusively in in-ear headphones (IEMs). They are mainly used by musicians or sound engineers to listen to mixes, as these drivers have the ability to output specific frequencies.
A good in-ear headphone can have up to four balanced armature drivers, and they need them in order to get a decent bass response. The sound they provide in the high and mid-tones is very detailed and has good noise isolation. They are more expensive than dynamic drivers.
Electrostatic drivers are typically used in more expensive headphones. They are the best in terms of sound resolution. They produce very high fidelity audio, with great amplitude and no distortion at all. They use a diaphragm that has been electronically loaded. Headsets using these drivers require headphone amplifiers to work.
What is headphone impedance?
For us, headphone impedance is the most important technical specification. In fact, when we evaluate the best headphones in our reviews, it's the first thing we look at. Not only because it tells us something about the behavior of the headphones, but also because it clarifies what we will need for them to be able to play music correctly.
Impedance is the electrical resistance. Basically, it's the resistance created by the magnet coils of the loudspeakers to the passage of current and it tells us how well or poorly the loudspeakers or headphones resist a certain electric current.
Even if you don't understand any of this, the impedance of the headphones is easy to interpret. It's measured in terms of ohms (Ω) and what it tells you is how much power your headphones need to get a reasonable volume of music. The more impedance they have, the more resistance they will put up and the more the signal will be weakened. The result? You will probably need an amplifier to squeeze them out.
Of course, the sound quality will be incredible. High-quality headphones often have a high impedance and require an amplifier capable of delivering adequate power to bring out the full brilliance of each sound.
The headphone impedance indicates how much you will have to increase the volume control before the sound can be perceived well. Why is this important? Because the higher the number in front of the symbol (Ω), the more power the headphones will need. It means that certain audio sources, smartphones for example, will not be able to provide the necessary power to the headphones.
Any impedance up to 32Ω can be reproduced by most mobile devices. With the 33-100Ω impedance you can probably get enough volume but you will need to add a headphone amplifier to improve performance, which increases power and improves sonic detail. Any impedance above 100Ω will require an amplifier. Today there are many devices are capable of handling up to 600Ω.
Why do you need to worry about high impedance headphones in the first place? The reality is that the best headphones on the market have a high impedance. This means that to get the most out of them, you will need amplifiers. This translates into more expense. Of course, once you plug them in, their sound will bring a smile to your face.
What is headphone sensitivity ( SPL )?
It's the measure of how loud a pair of headphones can sound at a certain power level. Headphone sensitivity, also sometimes called efficiency or SPL(Sound Pressure Level) is related to impedance, although it's not as important when deciding whether or not to buy a pair of headphones.
If headphones A have a higher sensitivity than headphones B at a power level of one milliwatt, then the audio produced by those headphones will be louder at that volume. This means that you will have to turn up the volume control less to get the level you want. A headphone sensitivity of 86dB is considered low, while anything above 110dB is considered a high level.
In reality, headphone sensitivity doesn't tell us much, as most companies are not very consistent in measuring this capability. If we add other variants at the time of reproduction, such as the sound source, the amplifier or the user's listening ability, the term sensitivity is almost useless.
It's much more important to find a pair of headphones that can reproduce the sound of the source loud enough, and this is told by the impedance. If we only have a phone or tablet, then we should find headsets up to 32Ω.
What is THD? (Total Harmonic Distortion)
This is an interesting specification. 90% of the time you don't need to pay attention to it, but it's a good indicator of headphone behavior. It's a measure that tells us how much the audio can change from the time it enters the headphones until it comes out, thanks to the drivers, in sonic form. This change is known as distortion, although it's not the distortion you get with a guitar pedal, for example.
The most important thing is that the total THD (Total Harmonic Distosion) is as low as possible. The less you change the audio in a pair of headphones, the higher the fidelity and sound quality. Today, headphone technology is so good that THD is measured in decimal points. A THD of 0.1% (meaning that the headphones distort no more than 0.1%) is common.
It should be mentioned, however, that just because a headset has a low THD doesn't mean that it will not give some color to the sound. You can think of THD as undesirable distortion, which can reduce the enjoyment of music delivered by the best headphones. It's actually not the most important aspect when choosing headphones.
Frequency (or frequency response) refers to the range of sound that a pair of headphones can reproduce: how low or high they can go (expressed in Hertz). The low frequency sounds, the bass, can range from around 60-500Hz, while the more defined high frequencies can sound around 16-17,000HZ (also written as 16-17kHZ, or KiloHertz).
It's useful to know this technical specification, although it's not the most important one. In theory, the higher the range, the more sounds the headphones can reproduce. But in practice…
In practice there may be loudspeakers with a frequency: 10Hz-23kHZ. This is nonsense. Why? Because a human being in their prime, at a young age and without having worn out their ears listening to loud music, can only hear sounds as low as 20Hz and as high as 17.4kHZ.
Any frequency lower or higher than this range is inaudible. This means one thing: if headphones can reproduce sounds at 23kHZ, it doesn't mean anything, because you won't be able to hear them. That's right. Don't get us wrong: the best headphones, with wider frequency ranges, such as those up to 22kHZ, can add a little more detail to the sound spectrum, but it's hardly noticeable.
Our advice is to ignore this specification when choosing your desired headphones, unless they have a lower than normal range, which may indicate that the headphones are not capable of doing their job. Any equipment that cannot reproduce frequencies lower than 30HZ or above 16kHZ is probably no good.
Types of headphones
Those are the main headphone specifications you need to know, but it's worth knowing something about the different types of headphones. The main ones are known as: over-ear (circumaural), on-ear (supra-aural) and in-ear (intra-aural). Here are some brief pros and cons of each type.
Circumaural / over-ear headphones
They are worn over the ear (which is what the word circumaural means) and have padded cups that completely envelop the ears. They tend to provide a deeper, higher quality sound than other types of headphones, but are also heavier and larger, making them less portable and sometimes more uncomfortable.
Supraural / on-ear headphones
They rest on the ears. They usually don't have the depth or sound quality of over-ears, but they are less expensive, portable and lightweight. You won't see many high-impedance on-ear headphones, as they are typically used with mobile devices.
In ear / in-ear earphones
We can divide these into two main subclasses: in-ear headphones, which are simple units with individual drivers that fit each ear, and in-ear (iEMs), which are somewhat more complex and usually offer multiple drivers, thus providing better sound.
Currently, the only disadvantage of in-ear headphones is that they can be uncomfortable during prolonged use. The best in-ear headphones can compete with the sound quality of on-ear equipment, but they can also be just as expensive.
Headphones features: What is the difference between closed and open headphones? Closed-back Vs open-back
Another aspect to consider is whether they are open or closed type headphones. When grabbing any pair of headphones, just look at the outside of the cups. If the surface is solid, then they are closed headphones. If they have some kind of grid or if you can see the driver, then they are open. Something simple, but that generates remarkable differences when listening to music.
Most of the time the sound provided by the best open headphones is excellent. These allow air to interact with the driver more easily and this gives the sound unique qualities. The open design makes the sound sound open and wide, with good detail.
Open headphones do not isolate sound well, which means that anyone next to you will be able to hear the music you are listening to. Also, they are not the best headphones to take with you outdoors, because you will also hear external noises.
Closed headphones do not have such a detailed sound, but this doesn't mean that they sound bad, in fact they tend to have a little more punch in the lower frequencies and are much better for listening in busy environments as they isolate much better.
Headphones specifications: Wireless or wired
We would also like to briefly mention the differences between wireless and wired headsets. Previously, wired headphones have always prevailed in terms of sound quality, but thanks to advances in Bluetooth technology and its various codecs such as aptX, the gap between the two has been greatly reduced. However, wired headsets are generally still superior in terms of audio quality.
The best high-impedance headphones, those that require a separate headphone amplifier, are wired. They are the best bet if you are looking for the best possible sound. Wireless headphones, on the other hand, are very comfortable and practical, since you can use them anywhere. If you are looking for comfort and simplicity, they are the best option.
Headphone features: Noise isolation and cancellation
The term noise isolation, or passive noise cancellation, refers to the ability of the headset to block out the noise around you. This refers to the effectiveness that the headphone seal achieves over your head to isolate you from external sound.
Active noise-cancelling headphones, on the other hand, use built-in microphones to capture sound from your surroundings and block it by reversing the polarity. The most effective are circumaural or over-ear headphones. If you usually listen to music in noisy environments, we recommend you take a look at CulturaSonora's selection of the best noise-cancelling headphones.
How do I know which headphones are the best?
How can you know which headphones are the best without trying them out in person? The quickest and easiest way is to read specialized reviews, which can give you a good idea of the unique capabilities of each model. For this you can check our website with confidence, we have compiled several lists with detailed reviews on all types of headphones designed for every user and circumstance.
If you want to go a step further, you can analyze the technical specifications of each model. That is why we have prepared this guide with all the terms you need to know to choose the ideal model for you. We leave you with a video about the differences between open-back and closed-back headphones: