Comparison Sony WI-XB400 vs Huawei FreeLace

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.

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.

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.

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 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.

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 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.

The main material used for the headphone housing.

Most modern headphones are made of plastic: it is inexpensive and at the same time practical, easy to process and well suited even for complex shapes. For such models, the case material is not indicated at all. However, there are more specific options, they can be as follows:

— Metal. The main advantages of metal cases are high reliability and a solid appearance — which also lasts quite a long time due to the resistance of this material to scratches. In addition, metal may also be the best option in terms of acoustics. At the same time, it costs much more than plastic, and therefore it is found mainly among fairly advanced models, including Hi-Fi class.

— Tree. Due to the characteristic colour and texture, the wood gives the headphones a pleasant and stylish appearance. In addition, it is also pleasant to the touch, and for many users, the wooden surface is associated with a “warm” and “soft” sound, which can significantly affect the subjective perception of the sound of headphones. At the same time, in reality, such a case has little effect on the sound quality, and the actual acoustic characteristics of such models may be different. Moreover, wood is rarely used in its pure form, it is usually combined with other materials — in this case, we are talking about plastic, the combination of wood and metal is placed in a separa...te paragraph (see below).

— Wood / metal. Usually, in this case, metal cases with wooden inserts are meant. See above for details on the features of these materials. Here we note that this option is considered more advanced than the “ordinary” tree (wood with plastic), however, it costs accordingly.

— Ceramics. Headphones typically use high-quality ceramics that are durable, reliable, and with advanced acoustic characteristics. At the same time, this material is very expensive. Therefore, it is found in single models, mainly in-ear "ears" of the top class — ceramics are not suitable for large cases, because such devices would be too fragile.

The headphones have special protection against moisture and dust; also, this clause may specify the level of such protection according to the IP standard.

Not all waterproof headphones allow complete immersion in water, but in this case this is usually not required — water protection is mainly intended for safe operation in the rain (or during sports activities when the user sweats a lot). But the specific degree of such protection in different models can vary markedly, and here it is most convenient to evaluate it by IP marking. This marking consists of the letters IP and two numbers; moisture resistance is described by the second, last digit, and in modern headphones you can find the following options:

— 2. Protection against vertical drops of water in the working position and when the device deviates up to 15 ° from this position. The minimum indicator that allows us to talk about resistance to rain (however, without strong winds).
— 3. Protection against splashes falling vertically or at an angle up to 60° from the vertical. Provides resistance to moderate rain and strong winds.
— 4. Splash proof from any direction. With such headphones, rain of medium intensity is not terrible, regardless of the strength of the wind.
— 5. Protected against water jets from any direction. Allows you to transfer already a combination of strong wind w...ith a downpour.
— 6. Protection against strong water jets. It is considered the minimum level that allows you to swim safely (with your head above the surface of the water) wearing headphones.
— 7. Possibility of short-term (less than half an hour) immersion under water to a shallow depth (less than 1 m); continuous operation in immersed mode is not expected. In such headphones, you can no longer only swim, but also dive under water to a shallow depth (plunge with your head), but they are not suitable for full-fledged diving.
— 8. The highest level of water protection actually found in modern headphones (although theoretically there is a higher level, level 9). Allows long-term (more than 30 minutes) immersion under water to a depth of 1 m or more, and even permanent work in a submerged position. And although the latter is not particularly relevant for headphones, however, this degree of protection makes it possible to swim and even dive safely. However, note that specific restrictions on use in such headphones may be different, they must be clarified according to the instructions.

As for protection against dust (it is indicated by the first digit in the IP marking), its level in modern “ears” is indicated mainly in cases where it corresponds to level 4 (protection against objects 1 mm thick or more), 5 (allowed a small amount of dust that does not affect the operation of the device) or 6 (complete protection against dust). Also note that this number can be replaced by the letter "X" — for example, IPX7; this means that no official dust certification has been carried out for this model. However, this resistance in many cases can be assessed by the degree of protection against moisture: for example, devices with a moisture resistance of 7 or 8, by definition, do not let water through — which means that they are also not afraid of dust.