Comparison Apple AirPods 2 with Charging Case vs Xiaomi Redmi AirDots

In this paragraph, first of all, the method of mount on the ears is specified; according to this parameter, modern headphones are divided into overhead, earbuds, in- ear, glasses and headbands. For on-ear models, the acoustic design (closed, semi-open, open) can also be specified here, as well as the presence of such features as a full-dimensions (over-ear) design (in the absence of this feature, such headphones are called “on-ear”, or simply on-ears), swivel earcups, auto-adjust headband, or even the mid-2021 trend, Cat Ears. And details such as a rigid headband, behind-the- ear mount, mount on the neck and the ability to fold can be combined with almost any method of placement on the ears (with a few exceptions - for example, on-ear models are not attached to the neck).

Here is a more detailed description of the different ear placement options:

- Overhead. Overhead headphones are called headphones that are located outside the auricles, covering the ear from the side (“regular” overhead models) or completely (full-sized Over-Ear - see below about them). In any case, such models are quit...e large in dimensions. This, on the one hand, simplifies the creation of headphones with advanced sound characteristics, and also allows you to apply some specific tricks without much difficulty - for example, several emitters or support for multi-channel surround sound. On the other hand, the dimensions of the "ears" complicate the transportation and use on the go. In addition, it is worth considering that most overhead models have a headband, which is why they are poorly compatible with complex hairstyles and some headdresses. Models with rigid temples and behind-the-ear fasteners do not have this disadvantage, but they also have their own specifics (see below).
On-ear headphones can have different acoustic design:

• Closed. Models with a high degree of sound insulation, protecting the user from extraneous sounds as much as possible. This design contributes to a rich sound (especially in the bass range) as well as a very powerful immersion effect, making it well suited for home use (including computer games) and noisy environments. But it is not recommended to use such “ears” on the street: complete isolation from surrounding sounds in such conditions can be unsafe. In addition, it is believed that a completely closed design slightly degrades the sound fidelity.
• Open. Headphones with a minimum level of sound isolation, allowing most of the external sounds to pass through. They are inferior to closed ones in terms of power and saturation of sound, as well as efficiency in noisy environments; in addition, the sound from such headphones is well audible to others. On the other hand, open models generally provide more authentic sound and are better suited for situations where you need to control your surroundings, such as outdoor applications.
• Semi-open. A kind of compromise between the options described above: headphones with better sound insulation than in open models, but still not up to closed “ears” in this indicator. For some users, this middle option may turn out to be more comfortable. In addition, semi-open headphones are also appreciated in professional work with sound: they retain the richness of the bass and at the same time do not create the distortion typical of a completely closed design.
• With rigid shackle. Rigid headband allows you to securely fix the ear pads on the ears. A close analogue of the rigid headband is the headband of full-dimensions headphones, but in contrast to it, the headband is worn on the back of the head, and not on the top of the head. For this reason, hard temples are made mostly without padding, from bare plastic/metal. Headphones with a rigid headband most often have a sports focus, because the headphones, located on the back of the head, will not fidget on the head even with intense running. On-ear headphones are pressed tightly against the auricles, but the speakers themselves are placed on the outside of the auditory canals.
• Cat Ear ("ears"). On-ear headphones in an interesting design - with an imitation of cat ears on the headband. Such an addition does not affect performance, however, the "ears" look unusual and can be a great addition to the bright, original style of the owner. Cat Ear headphones are especially popular among teenagers.

- Intrachannel. Tiny earphones that, when used, are inserted directly into the ear canals. For ease of wearing, rubber or silicone pads are provided, often several of these pads are included in the kit to adjust to a specific ear dimensions. This design combines compactness and advanced performance: earbuds “ears” are often comparable to overhead ones in terms of sound volume and bass saturation, and the degree of sound insulation is very high (many models can even be used as impromptu earplugs). On the other hand, complete isolation from external sounds can sometimes be a disadvantage - for example, when cycling or walking along a busy street.

- Intracanal with a rigid shackle. In-ear headphones are laid inside the auditory canals, which allows them to be fixed as securely as possible in the ear and not fall off. The presence of a rigid bow further increases the reliability of fixing the headphones. This type of headphone is well suited for sports. The rigid headband and earbuds design of the sound emitters keep the earbuds securely in place even during intense running.

- Inserts. Also known colloquially as "pills". Similar to earbuds headphones, these headphones are small in dimensions and are placed in the auricle - however, not in the depth of the auditory canal, but at its very beginning, almost outside. This makes the earbuds somewhat simpler in design and cheaper, but it is more difficult to achieve rich sound and advanced acoustic characteristics in them. Such models give a rather low sound insulation, but this can be both a disadvantage and an advantage, depending on the situation. And some headphones of this type have an elongated shape, due to which they sit deeper in the ears and, in terms of their capabilities, can approach earbuds models.

Separately, it is worth noting that earbuds models and earbuds do not use headbands - the headphones are either completely separate or connected with a device such as a rigid headband or neck mount. So these headphones can be worn with almost any hairstyle or headdress without any problems.

— Inserts with a rigid headband. The earbuds are simply inserted into the passage of the auditory canal without penetrating deeply into it. This is not the most reliable way to fix the headphones, but due to the presence of a rigid headband, the earbuds gain a firm fit and a secure fit. The headphones themselves have an open sound path design, and therefore reproduce audio with a noticeable distortion of the original sound signal. But at the same time, the open acoustics scheme allows you to clearly hear what is happening in the surrounding space.

As for additional design features, they can be as follows:

- Full-dimensions Over-Ear. On-ear headphones (see above) in which each cup completely covers the ear and fits snugly to the head. The cups themselves in such models are made quite large and are equipped with characteristic soft "borders" around the perimeter of the inner side - these borders are adjacent to the head, so that the auricle is actually inside the cup. The main advantage of this design is that the headphones (with the right dimensions) practically do not touch the user's ears and do not put pressure on them - this is especially comfortable during prolonged use. In addition, it is easier to achieve high-quality sound insulation in Over-Ear models (although among them it is quite possible to find models with semi-open and even completely open acoustic design). The main disadvantage of such devices is bulkiness and inconvenience in transportation and use on the go. In addition, when wearing glasses, the Over-Ear cups usually press on the temples from the sides, which can cause discomfort.

- Auto headband adjustment. A headband that can automatically adjust to the dimensions of the user's head. Such a headband usually consists of two parts - a rigid, usually metal, base, and a soft inner part, which is adjacent directly to the head. It is the inner part that is able to stretch, and the user only needs to place the cups on the ears so that it is comfortable - and the headband itself will increase to the desired dimensions.

- Rigid bow. A shackle made of rigid material that connects both headphones and is located on the back of the head when worn; in some models it can also serve as a neck mount (see below). The advantage of such a device over the classic headband is that the bow can be used with almost any hairstyle and headgear. On the other hand, in earbuds models and earbuds (see above), this feature makes the headphones more bulky, and in over-ear models it makes sense to use it only with conventional models that are not related to full-dimensions Over Ear. Therefore, as well as for a number of other reasons, in our time the bow is not particularly popular.

- Ear mount. Attachment that allows you to fix each earpiece directly on the ear; as a rule, it has the appearance of a characteristic bow. This feature is found in all types of modern "ears", except for Over Ear (see above), and its specific meaning depends primarily on the main way the earpiece is placed on the ear. So, for earbuds models and earbuds, the behind-the-ear mount provides additional reliability of retention: the likelihood that the earpiece will fall out of the ear is reduced to almost zero due to such a retainer. In overhead "ears" this feature is much less common, and its main idea is to do without a headband or a rigid headband - in some cases, these design elements are redundant.

- Attachment to the neck. A feature that is found exclusively in wireless and combined models (see "Connection type") - and only earbuds and earbuds (see above). Both headphones in such models are connected to each other either with a regular wire with a thickened part, or with a special horseshoe-shaped hoop (a separate “ear” is connected to each end of such a hoop with a wire). In any case, when worn, such a wire or hoop is located at the back of the user's neck, which provides additional convenience: headphones removed from the ears (or dropped out) do not fall to the ground, but remain hanging on the mount. And in some models, special magnets are also provided, with which you can “stick” the headphones taken out of your ears to each other, turning the entire structure into a ring - this further reduces the risk of dropping the device.

- Possibility of folding. The earphones can be folded compactly for storage and transport. Note that this feature is indicated only for overhead models (see above) - earbuds headphones and earbuds are quite portable in themselves, there is no need to provide a special folding design for them.

- Swivel bowls. A design feature found in over-ear headphones (see above). Rotary in this case means bowls that, in the working position, can be rotated at a certain angle around the vertical axis. This allows the headphones to further adapt to the dimensions and shape of the user's head - which, in turn, increases comfort, especially when worn for a long time. On the other hand, the swivel mount somewhat complicates the design of the headphones, increases its cost and somewhat reduces reliability.

- Glasses. Headphones in the form factor of glasses. The sound of such models is transmitted either by directional speakers built into the temples, or directly to the inner ear by conduction through the bones of the skull. In addition to music, bone conduction glasses provide audibility of what is happening around.

- Headband. Headbands with built-in earphones. In a similar format, children's's models of headbands with bright prints of cartoon characters and fairy-tale characters are produced, as well as headbands for fans of a sports lifestyle. Headphones in such models are usually made removable, which allows you to wash the headband.

Range of wireless-capable headphones (see "Connection type").

When evaluating the range, it should be taken into account that this parameter is rather conditional and the actual range may differ slightly from the claimed one (usually in a smaller direction). So, when connecting via a radio channel, the range is indicated for perfect conditions — without interference and obstacles in the signal path. For Bluetooth models, the range also depends on the power of the Bluetooth module in the device to which the “ears” are connected. And the effectiveness of the IR channel may be reduced in hot weather or in bright sunlight. So when choosing according to this indicator, it's ok to take a certain margin.

On the other hand, there are two points worth noting. Firstly, in general, the specified range accurately describes the capabilities of the headphones, and it is quite possible to evaluate and compare different models with each other. Secondly, even in the most modest wireless “ears”, the communication range is about 8–10 m, 11–20 m is considered an average, and a fairly large number of devices can operate at distances of tens and even hundreds of metres. So paying attention to the range makes sense mainly in cases where you plan to move away from the signal source at a considerable distance — from 5 m or more — or listen to sound through walls.

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.

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.

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.

A function that allows you to automatically pause the playback track when you remove the headphones (or one headphone).

Autopause is found mainly in wireless models (see "Connection Type") true wireless format (see "Cable Type"); however, there are other types of headphones with this function — for example, with a combined connection and an overhead design. Anyway, the proximity sensor is usually responsible for the auto-pause operation, which is triggered when the earpiece moves away from the ear. This feature is especially useful in situations where, after removing the headphones, there is no time to manually pause playback — for example, you need to urgently respond to what is happening nearby. At the same time, some models are able to automatically resume playback when the earpiece is returned to its place, however, this function is not strictly required — it will not hurt to clarify its presence separately.

A technology used in Bluetooth models (see "Connection") that allows the headphones to connect to multiple devices at the same time. Thanks to this, you can, for example, listen to music from a laptop, and when a call comes in on a mobile phone, switch the headphones to a conversation. This technology has its own characteristics for different manufacturers, and therefore, if the multipoint function is critical for you, you should separately clarify the details of its operation in the selected model.

Codecs and additional audio processing technologies supported by Bluetooth headphones (see “Connection”). Initially, sound transmission via Bluetooth involves fairly strong signal compression; This is not critical when transmitting speech, but can greatly spoil the impression when listening to music. To eliminate this shortcoming, various technologies are used, in particular aptX, aptX HD, aptX Low Latency, aptX Adaptive, AAC, LDAC and LHDC. Of course, to use any of the technologies, it must be supported not only by the “ears”, but also by the Bluetooth device with which they are used. Here are the main features of each option:

- aptX. A Bluetooth codec designed to significantly improve the quality of audio transmitted over Bluetooth. According to the creators, it allows you to achieve quality comparable to Audio CD (16-bits/44.1kHz). The benefits of aptX are most noticeable when listening to high-quality content (such as lossless formats), but even on regular MP3 it can provide a noticeable sound improvement.

- aptX HD. Development and improvement of the original aptX, allowing for sound purity comparable to Hi-Res audio (24-bits/48kHz). As in the original, the benefits of aptX HD are noticeable mainly on high-quality...audio, although this codec will not be out of place for MP3.

- aptX Low Latency. A specific version of aptX described above, designed not so much to improve sound quality, but to reduce delays in signal transmission. Such delays inevitably occur when working via Bluetooth; They are not critical for listening to music, but when watching videos or playing games, there may be a noticeable desynchronization between the image and sound. The aptX LL codec eliminates this phenomenon, reducing latency to 32 ms - such a difference is imperceptible to human perception (although for serious tasks like studio audio work it is still too high). aptX LL support is found mainly in gaming headphones.

- aptX Adaptive. Further development of aptX; actually combines the capabilities of aptX HD and aptX Low Latency, but is not limited to this. One of the main features of this standard is the so-called adaptive bitrate: the codec automatically adjusts the actual data transfer rate based on the characteristics of the broadcast content (music, game audio, voice communications, etc.) and the congestion of the frequencies used. This, in particular, helps reduce energy consumption and increase communication reliability; and special algorithms allow you to broadcast sound quality comparable to aptX HD (24 bits/48 kHz), using several times less amount of transmitted data. And the minimum data transfer latency (at the aptX LL level) makes this codec excellent for games and movies.

- aptX Lossless. The next stage in the development of aptX technology, which involves transmitting CD-quality sound over a wireless Bluetooth network without loss or compression. Audio broadcasting with sampling parameters of 16 bits / 44.1 kHz is carried out with a bitrate of about 1.4 Mbit/s - this is about three times faster than it was in the aptX Adaptive edition (see above). Support for aptX Lossless began to be introduced at the end of 2021 as part of the Snapdragon Sound initiative from Qualcomm.

- A.A.C. A Bluetooth codec used primarily in portable Apple gadgets. In terms of capabilities, it is noticeably inferior to more advanced standards like aptX or LDAC: the sound quality when using AAC is comparable to an average MP3 file. However, for listening to the same MP3s, this is quite enough; the difference becomes noticeable only on more advanced formats. AAC hardware requirements are low, and its support in headphones is inexpensive.

— LDAC. Sony's proprietary Bluetooth codec. It surpasses even aptX HD in terms of bandwidth and potential sound quality, providing performance at the Hi-Res level of 24-bits/96kHz audio; there is even an opinion that this is the maximum quality that it makes sense to provide in wireless headphones - further improvement will simply be imperceptible to the human ear. On the other hand, supporting this standard is not cheap, and there are still quite a few gadgets with such support - these are, in particular, Sony smartphones, as well as mid- and high-end devices running Android 8.0 Oreo and later versions.

- LHDC. LHDC (Low latency High-Definition audio Codec) is a high-definition, low-latency codec developed by the Hi-Res Wireless Audio Alliance and Savitech. In the vast majority of cases, its support is implemented at the hardware level in Huawei and Xiaomi smartphones. The codec is also known as HWA (Hi-Res Wireless Audio). When using LHDC, signal transmission from the phone to the headphones is carried out with a bits rate of up to 900 kbps, a bits depth of up to 24 bits and a sampling frequency of up to 96 kHz. This ensures a stable and reliable communication with reduced latency. The codec is optimally suited for high-end wireless headphones and advanced digital audio formats.