Frequency range
The range of sound frequencies that headphones can reproduce.
The
wider this range, the more fully the headphones reproduce the spectrum of sound frequencies, the lower the likelihood that too low or too high frequencies will be inaccessible. However, there are some nuances to consider here. First of all, let us remind you that the perceptual range of the human ear is on average from 16 Hz to 22 kHz, and for the complete picture it is enough for headphones to cover this range. However, modern models can significantly exceed these boundaries: in many devices the lower threshold
does not exceed 15 Hz, or even
10 Hz, and the upper limit can reach
25 kHz,
30 kHz and even
more. Such wide ranges in themselves do not provide practical advantages, but they usually indicate a high class of headphones, and are sometimes given only for advertising purposes.
The second important point is that a wide frequency range in itself is not a guarantee of good sound: sound quality also depends on a number of parameters, primarily the amplitude-frequency response of the headphones.
Sensitivity
Rated headphone sensitivity. Technically, this is the volume at which they sound when a certain standard signal from the amplifier is connected to them. Thus, sensitivity is one of the parameters that determine the overall volume of the headphones: the higher it is, the louder the sound will be with the same input signal level and other things being equal. However, we must not forget that the volume level also depends on the resistance (impedance, see above); moreover, it is worth choosing “ears” for a specific device first by impedance, and only then by sensitivity. In this case, one parameter can be compensated for by another: for example, a model with high resistance and high sensitivity can work even on a relatively weak amplifier.
As for specific figures, headphones with indicators of 100 dB or less are designed mainly for use in a quiet environment (in some similar models, the sensitivity
does not exceed 90 dB). For use on the street, in transport and other similar conditions, it is desirable to have more sensitive headphones — about
101 – 105 dB, or even
110 dB. And in some models, this figure can reach
116 – 120 dB. and even
more.
It is also worth noting that this parameter is relevant only for a wired connection according to the analogue standard — for example, via a 3.5 mm mini-
...jack. When using digital interfaces like USB and wireless channels like Bluetooth, the sound is processed in the built-in headphone converter, and if you plan to mainly use this kind of application, you can not pay much attention to sensitivity.Harmonic distortion coefficient
The coefficient of harmonic distortion produced by this model of headphones.
This parameter determines the amount of non-linear distortion introduced by the headphones into the reproduced sound. The lower it is, the less such distortions, the cleaner and closer to the original sound is. So, an indicator of 1% or more can be considered tolerable at best, from 0.5% to 1% — good, less than 0.5% — excellent (such indicators are acceptable even for monitor headphones), and less than 0.1% — almost perfect.
Note that a low harmonic coefficient in itself does not guarantee high-quality sound — a lot depends on other features of the headphones, primarily the frequency response.
Microphone
The location of the
microphone, which the headphones are equipped with (if available, of course).
— On the cable. A microphone installed on the headphone connection wire (or on the connection cable in non-TWS wireless headphones). Can be combined with
volume control. This option allows you to separate the microphone and headphones, reducing the weight and dimensions of the "ears" themselves; on the other hand, the microphone when worn is often quite far from the face, which can be inconvenient. Therefore, this design is mainly used among earbuds and in-ear
headphones, where the size of the "ears" is critical.
— Built into the body. A microphone located in the housing of one of the headphones. This arrangement is convenient because there are no extra protruding parts outside (as in
headphones without a microphone), while the microphone is close to the face, and in some models it is also able to perceive sound according to the principle of bone conduction. However installation in close proximity to the speaker gives additional interference and may degrade the quality of voice transmission. However, these shortcomings are not critical: interference can be compensated, and the built-in headphone microphones, in fact, do not need perfect sound transmission accuracy. Therefore, this option is quite popular nowadays, and it is fo
...und not only in miniature models, for which the absence of unnecessary details on the outside is important, but also in rather large overhead "ears".
— On the bow. A microphone mounted on a small boom that is attached to one of the headphones. The microphone on the bow is the most popular among overhead headphones: a large cup can be supplemented with a boom without sacrificing convenience, and the microphone itself is located far from the headphones, which has a positive effect on the purity of the sound. The boom often has a swivel or detachable mount, which allows you to remove the microphone from the face until it is needed (by lifting the boom vertically along the headband).
— Retractable on the bow. Headband microphone (see above) with a retractable design: the headband can be pulled out of the cup when needed and can be tucked back inside when not in use. These headphones are more compact and have a neater appearance than models with a headband on a swivel mount: in a hidden position, the microphone takes up almost no space outside. The retractable microphone design is especially popular in gaming models (see “Intended Use”): in single-player games where you do not need to communicate with comrades, the microphone can be folded compactly.
— Removable on the shackle. Headband microphone (see above), which can be completely detached from the headphones if desired. Such a design can be useful, for example, if the “ears” are used both as gaming and as “marching and musical”: in a multiplayer game, the microphone is indispensable, and for listening to music outside the home, it can be removed so as not to carry extra equipment (which besides, you can lose).
— At the receiver. A variant used in wireless headphones with a separate receiver. In terms of design and use, it is similar to the microphone on the cable described above: on the one hand, the headphones themselves can be very light and tiny, on the other hand, the microphone may not be located close enough to the face, and when talking it will have to be brought closer.
— In the mount. In this case, most often means a microphone mounted on a neck mount (see below). This option is found mainly among wireless headphones, which have a signal receiver in the same mount. Such a microphone is located close to the neck, which allows you to achieve good speech intelligibility and at the same time cut off extraneous sounds even without any special additional tricks.
— On the cable and in the case. Headphones equipped with two microphones — one in the case, the other on the cable. The features of these variants are described in detail above. Here we note that their combination is extremely rare, mainly among high-quality "ears" with a combined connection (see "Type of connection"). In such models, when working via a wireless channel, a microphone in the case is used, and when connecting a wire, a microphone on a cable is used, which is less susceptible to interference.
— On cable and removable. Another kind of headphones with two microphones, also quite rare. One microphone in such models is mounted on a cable, the second — on a detachable bow. See above for more on each of these options, and combining them allows you to tailor the headphones to the specific situation. For example, the bow is very convenient for voice communication at home or office computers, but on the street and in transport it is better to remove it and use the microphone on the cable.
— In the case and removable. A rather rare and non-standard option is the combination of a microphone in the case and a microphone on a detachable bow. See above for more details on each of these varieties, and their combination is used quite rarely — in separate premium gaming models with a combined connection. The main point in this case is that it is more convenient to use a removable microphone in one place, with a wired connection, and in the “mobile” wireless mode it is better to remove it and get by with the built-in microphone. However, such features are fundamental mainly for the most demanding users, so this option has not gained distribution.Frequency range
The range of audio frequencies that the headphone's own microphone can normally "hear".
Theoretically, the wider this range, the more advanced and high-quality the microphone is, the closer the sound transmitted by it is to the real one. In fact, extensive frequency coverage is not always required. So, the working range of the human ear is about 16 – 22,000 Hz, and even then not everyone hears its upper part. And human speech usually covers frequencies from 500 Hz to 2 kHz, at least this range is considered quite sufficient for its transmission. So if you need a microphone for simple tasks like voice communication on the Internet or game chat, you can not pay much attention to the frequency range: even in the most modest models, it is more than sufficient for normal speech transmission.
Sensitivity
The sensitivity of the headphone's own microphone.
The more sensitive the microphone, the higher the signal level from it, at the same sound volume, and the better this model is suitable for picking up quiet sounds. Conversely, low sensitivity filters out background noise. At the same time, we note that these nuances are important mainly in professional work with sound. And for simple tasks like voice communication over the phone or via the Internet, sensitivity does not really matter: in headphones of this specialization, it is selected in such a way as to ensure that the microphone is guaranteed to work.
Microphone mute
The ability to turn off your own headphone microphone using a special button or switch.
This feature is relevant mainly for phone calls, Skype, etc. It is useful in situations where you need to distract from the main conversation and say something that the interlocutor does not need to hear. Disconnecting the microphone is easier and more reliable than covering it with your hand or disconnecting the headphones entirely.
Note that the
ability to turn off the microphone may be provided in the communication programme itself (the same Skype, for example). However, again, using the switch on the headphones is more convenient.
Flexible design
This feature usually means that the microphone is attached to the headphones using a special flexible arm.
The flexible design gives additional possibilities for moving the microphone relative to the user's mouth and makes it easier to choose the optimal position that provides the best sound quality.
Charging time
The time required to fully charge the battery in properly powered headphones (see above).
In this case, we mean the battery charging time from 0 to 100% when using a standard charger (or a third-party charger with identical characteristics). Accordingly, in fact, this indicator may differ from the claimed one, depending on the specifics of the situation. However, in general, it is quite possible to evaluate different models and compare them with each other: headphones with a shorter claimed charging time will in fact charge faster (ceteris paribus).
Also note that an increase in battery capacity (and headphone battery life) inevitably implies an increase in charging time. To compensate for this moment, special fast charging technologies can be used — however, they affect the cost and require the use of specialized charger.