Guest Post From PickyEar: Understanding Headphone Specifications

Headphone specifications have become a big topic of conversation, perhaps even too big. While we can all agree on them being helpful, people tend to follow them blindly. Definitely not the way to go. You've got your ears for one reason and one reason only - namely to sort good sounding headphones from bad sounding headphones. Okay, that might be overstating it, but I really want you to take this message home. Headphone specifications is a helpful tool. A guide. Nothing more, nothing less. Your ears are the judge.

Of course, to use the specs as a guide you need to understand them, and that's exactly what this article is going to cover. First, we are going to take a look at the most important specifications. Finally, we are going to discuss how to actually compare headphones. As you will discover, there is much more to it than simply comparing specs.

The Specifications
Whenever you encounter a pair of headphones, you'll encounter a list of specifications. These include the likes of frequency responseimpedance, and sensitivity. Some are more important to keep an eye on than others.

Frequency Response
One of the first things you'll see is the Frequency Response. Sound is measured in frequency. A high frequency corresponds to a high pitch, while a low frequency corresponds to a low pitch. The frequency response is show as a range. It goes from a low number, measured in Hz, to a higher number, measured in kHz.

 It tells you which frequencies the headphones will be able to present to you. The human ear is capable of hearing sounds between 20 Hz - 20 kHz (20,000 Hz). This is the minimum range that you want to see (Dynamic drivers have a wider range, Balanced Armature drivers can have lower than 20,000Hz stated as they struggle in the high frequencies but this is not a problem as most people can't hear up to 20,000Hz anyway).

Anything less, and you might not be able to hear all the sounds in your music. Anything higher is, of course, fine, but there isn't much sense in going too high (or too low), as you won't be able to hear the sounds. But companies do have optimistic specifications most of the time, so don't take the stated frequency response as true.

Take the Dunu DN-2000, for example. They have a frequency range that goes from 10 Hz - 30 kHz. While you won't be able to hear the lower and higher limits but it usually means there will be less distortion as the driver is not being stressed at lower or higher frequencies.

The impedance, sometimes called resistance, is measured in Ohms (Ω). A high impedance provides a clearer tone, as well as a reduced chance of getting noise on the signal. The downside is that it takes more power to run a pair of high impedance headphones. Thus, your iPod or iPhone might not be able to drive them at sufficient volumes. Headphones with a high impedance might require an external amplifier

Whether or not you will need an amplifier is a complicated subject, and will not be discussed in this article. However, as a general rule, the bigger the headphones, the more likely they'll benefit from an amplifier.

High impedance require more voltage but less current, Low impedance require more current but less voltage (portable batteries are low voltage thus for the most part low impedance is better in portable situations). High impedance is better in series also, so better in studio setups where multiple headphones are run in series, as it puts less strain on the amp.

Low impedance headphones typically range from 16Ω to 32Ω, while high impedance headphones range from 100Ω to 600Ω. Impedance only really becomes a problem when considering high-end headphones. 

In-ear phones rarely have a higher impedance than 32Ω and most can be driven perfectly fine with MP3 players, while high-end headphones often have an impedance of 100Ω+, and will most likely need an external amplifier to run at sufficient volumes. 

Ultra low impedance (less than 16Ω usually) balanced armature headphones usually run better with an amplifier though, as the damping factor comes in to play, along with the impedance curve.

The sensitivity is a measure of how effectively a pair of headphones converts an incoming electrical signal into sound. It tells you how loud the headphones will be able to play at a given level of power. Sensitivity is measured in dB/mW or dB/V. An efficient pair of headphones will have a sensitivity level of around 100 dB/mW. 

Efficient headphones are less likely to need an amplifier and will sound louder than a less efficient pair of headphones at the same volume. It is important to look at the sensitivity as some have low impedance but also low sensitivity, this will not be good for a portable headphone.

A high sensitivity means that the headphones will respond well to a wide range of power outputs. A downside is that they can't take as much of a beating as the lower sensitivity ones.

Closed Back vs. Open Back
This is more of a headphone type consideration than an actual spec. It is, nonetheless, every bit as important as the ones above. This mainly concerns full size headphones (but some in-ear headphone have an open back).

Closed back headphones will provide a better sound isolation than open backs will. This makes closed backs better in noisy environments. Open backs usually sound better than the closed backs (subjective). So if you aren't worried about outside noise, open backs might be exactly what you're looking for.

There is no answering which type of headphone back is better, as it all depends on application and preference. If you just want as good a sound as possible, go with an open back (of course this depends on all of the above). If you want noise isolation, or are going to be recording in a studio, go with closed backs. Studio headphones are a beast of its own. It's usually only technicians and musicians who will need them(although some like their reference sound at home). You can read more about them here, if you're interested.

Comparing Headphones
Now that you know your specs, it's time to set them aside for a minute. As I mentioned earlier, specs are only guidelines. At worst, they might even end up clouding your judgment. Take frequency response for example. Two headphones might have the exact same frequency range, but the frequencies might be boosted completely differently. One pair might play the mid level frequencies much louder than the rest, while the other headphones might play the bass tones at too low a volume. Frequency response, or any spec for that matter, won't be able to specify these sound signatures, so try looking for a frequency response graph (innerfidelity and headroom have lots).

So how do you actually compare headphones? Well, what I usually do is, I start by looking at the specifications. I don't want anything with a frequency range of less than 20 Hz - 20 kHz for example. For impedance and sensitivity, I don't have any preferences. I just don't want them to be absurdly high or low. And that's it!. We're done with the specifications. Digging any more won't do you any good, and at worst might cloud your judgment.

Once you've got a few headphones that you like the look of, it's time to read some reviews. Good reviewers spend a lot of time testing and reviewing their headphones. Read a couple of reviews on the headphones you've got an eye on. Make sure the reviewers are genuine reviewers, who take their reviews seriously (SoundPerfectionReviews is a great place to start).

Reading reviews should narrow your headphone list down even further. Now you've got two options. You can either dig deeper, reading the reviews more thoroughly. Or, if at all possible, (which I recommend) go to your local headphone store and actually listen to the headphones. Let's say you've narrowed your list down to 3 headphones. Go to your local store and ask if you can give these 3 headphones a try. You know they're good, since you've done your research. Now all that is left is figuring out which ones are the perfect fit for your ears.

That's what it's all about. Every individual's ears are different. We're looking for the best headphones for our ears. In fact, that's all we can do. We can't predict what other people will like, which is exactly why all reviews are subjective opinions. The final verdict needs to be yours. That's how you find the best headphones that fit your needs!

Written by 
Hogni Kamban