Comparison Meizu POP 2 vs Xiaomi Redmi AirDots

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.

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.

The diameter of the speaker installed in the headphones; models with multiple drivers (see "Number of drivers"), usually, the size of the largest speaker is taken into account, other dimensions can be specified in the notes.

In general, this parameter is relevant primarily for over-ear headphones (see "Design"). In them, emitters can have different sizes; the larger it is, the more saturated the sound is and the better the speaker reproduces the bass, however, large emitters have a corresponding effect on the dimensions, weight and price of the headphones. But in-ear "ears" and earbuds, by definition, have very small speakers, and rich bass in them is achieved due to other design features.

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.

The headphones have their own volume control. Such a regulator can be placed both on the wire and on one of the cups (the latter is typical for wireless models). Anyway, this function allows you to easily adjust the volume: for this you do not need to go into the computer settings, press the buttons on the player or smartphone, etc., just use the control at hand. On the other hand, additional equipment complicates and increases the cost of the design, and also increases the likelihood of distortion. In light of the latter, volume control is almost never found in professional headphones.

The capacity of the battery installed in the headphones of the corresponding design (see "Power").

Theoretically, a higher capacity allows to achieve greater battery life, but in fact, the operating time also depends on the power consumption of the headphones — and it can be very different, depending on the characteristics and design features. So this parameter is secondary, and when choosing it is worth paying attention not so much to the battery capacity, but to the directly claimed operating time (see below).

The capacity of the battery installed in the case (case) for headphones.

This parameter is relevant only for true wireless models (see "Cable type"). Recall that these headphones are charged from a case, which is usually equipped with its own battery and actually works in standalone power bank mode. Knowing the capacity of the battery in the case and in the headphones, you can estimate how many charges of the “ears” will last for one charge of the case. However, it should be taken into account that in the process of charging the headphones, part of the energy is inevitably spent on third-party losses, and the effective capacity of the case turns out to be somewhere 1.6 times less than the claimed one. This is the starting point for calculations: for example, a 300 mAh case will actually be able to transfer 300 / 1.6 = 187 mAh of energy to the headphones, and 30 mAh “ears” from such a battery can be fully charged about 6 times (187 / 30 ≈ 6).

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.

The type of connector used to charge the built-in headphone battery, 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 the appropriate cable is available). At the same time, in true wireless models (available with a long stem, a short stem, without a stem, with a behind-the-ear mount and a clip (Clip-on)), the “charger” wire is connected to a special docking station, where the “ears” are placed during charging (with In this case, 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 headphone body itself. As for connectors, the most common options are:

- microUSB. A smaller version of the USB connector designed for portable devices. It appeared quite a long time ago, but does not lose popularity in our time and is used by the vast 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 double-sided design, thanks to which the plug can be...inserted into the socket on either side. It is still relatively rare, but the situation is likely to change in the coming years.

- Lightning. Apple branded connector. Like USB C, it has a reversible design, while being somewhat more convenient and reliable, but the use of Lightning is limited to products from Apple itself and its Beats brand.