Hi-Res Audio
Headphone support for Hi-Res Audio. The corresponding format is designed to provide a sound close to that recorded in the studio.
Hi-Res Audio refers to a digital signal with parameters from 96 kHz / 24 bits, and for analog technology, the requirement for an extended frequency response is set from 40 kHz. Audio tracks in this format sound as close as possible to the original ideas of the authors of the compositions. The Hi-Res license marks premium headphones for avid audiophiles.
Impedance
Impedance refers to the headphone's nominal resistance to AC current, such as an audio signal.
Other things being equal, a higher impedance reduces distortion, but requires a more powerful amplifier — otherwise the headphones simply will not be able to produce sufficient volume. Thus, the choice of resistance depends primarily on which signal source you plan to connect the "ears". So, for a portable gadget (smartphone, pocket player), an indicator of
16 ohms or less is considered optimal,
17 – 32 ohms is not bad. Higher values —
33 – 64 ohms and
65 – 96 ohms — will require quite powerful amplifiers, like those used in computers and televisions. And models with a resistance of
96 – 250 ohms and
above are designed mainly for Hi-End audio equipment and professional use; for such cases, detailed recommendations for selection can be found in special sources.
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.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.
Operating time (music)
The declared operating time of headphones with autonomous power supply (see above) when listening to music on a single battery charge or a set of batteries.
As a rule, the characteristics indicate a certain average operating time in music listening mode, for standard conditions; in practice, it will depend on the intensity of use, volume level and other operating parameters, and in models with replaceable batteries - also on the quality of specific batteries. However, based on the stated time, you can fairly reliably assess the autonomy of the selected headphones and compare them with other models. As for specific values, relatively “short-lived” devices have a battery life
of up to 8 hours, a figure of
8 – 12 hours can be called quite good,
12 – 20 hours – very good, and in the most “long-lasting” headphones the operating time can
exceed 20 hours.
Operating time (no noise canceling)
How long does the active noise canceling headphones (see above) last on a single battery charge (or a set of batteries) when noise canceling is not used.
This function is quite “gluttonous” in terms of battery consumption, up to half of the total energy consumed by the headphones can go to its work. Thus, models with noise reduction can indicate both overall battery life (see "Operating time"), and battery life with the noise reduction turned off.
Charging port
The type of connector used to charge the built-in battery of the headphones, or more precisely, to connect an external charger. The role of such a device can be played by a network or car adapter, a power bank, or even a USB port of a PC or laptop (if there is an appropriate cable). At the same time, in true wireless models (there are
with a leg,
without a leg,
with an ear mount and
clips (Clip-on)), the "charger" cable is connected to a special docking station, where the "ears" are placed during charging (while the station itself usually has its own battery and can also work as an autonomous power bank). And in wireless and combined solutions of a more traditional design, the charging input is often located on the body of the headphones themselves. As for the connectors, the most common options are the following:
—
microUSB. A smaller version of the USB connector, created for portable devices. It appeared quite a long time ago, but it has not lost its popularity in our time, and is used by the absolute majority of manufacturers.
—
USB C. A miniature USB connector, positioned, among other things, as a potential successor to microUSB. Unlike its predecessor, it has a two-sided design, thanks to which the plug can be inserted into the socket from either
...side. It is still relatively rare, but the situation is likely to change in the coming years.
— Lightning. Apple's proprietary connector. Like USB C, it has a two-sided design, and is somewhat more convenient and reliable, but the use of Lightning is limited to products from Apple itself and its Beats brand.Touch control
This feature means that the controls in the headphones are not traditional buttons that you need to press, but sensors that are triggered by touch.
Touch control is somewhat more expensive than push-button control, but it has a number of advantages over it. Firstly, it gives the headphones a neat and technological appearance, with a minimum of protruding parts. Secondly, due to the absence of moving parts, the sensors are more reliable and compact. Thirdly, it is purely physically more convenient to use them, especially with the small size of the headphones. These moments are especially relevant for the "ears" of the true wireless format (see "Type of cable"), so it is in them that touch control is most often found. However, there are exceptions to this rule. Also note that the difference in price between buttons and sensors is often almost imperceptible compared to the cost of headphones in general.