Comparison Xiaomi True Wireless Earphones 2 Pro vs Xiaomi Mi Air 2 Pro

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 presence of a noise reduction system in its own headphone microphone.

In accordance with the name, such a system is designed to eliminate extraneous noise - primarily during conversations. It is usually based on an electronic filter that passes the sound of a human voice and cuts off background sounds such as city noise, the rumble of wind in the microphone grille, etc. As a result, even in noisy environments, thanks to the noise reduction of the microphone, speech is clear and intelligible; True, the system inevitably introduces distortions into the final sound, but they are not critical in this case.

— ENC. ENC (Environment Noise Cancellation) technology significantly reduces ambient noise with directional microphones. It is used both in gaming devices so that gamers can easily communicate in voice chat, and in TWS earphone models so that you can comfortably talk on the phone in a noisy environment.

— cVc. Microphone noise reduction cVc (Clear Voice Capture) is an advanced technology that is found mainly in expensive headphone models. cVc algorithms effectively suppress echo and noise from the environment. Sound processing using this technology is carried out at several levels at once - the algorithm determines the reference signal-to-noise level, automatically adjusts speech to the desired volume level, applies adaptive equalizers to process the entire voice, as well as specialized filters to remove...low-frequency bubbling, sibilants and hissing.

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 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 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 maximum operating time of TWS headphones, taking into account recharging with a native case. But this time is not continuous use, it takes into account breaks for "refueling". Anyway, this parameter allows you to understand for how long you can leave the network (for example, how many nights to spend in a tent to the accompaniment of your favorite artist).

The function reduces the charging time of the headphones compared to the duration of the standard procedure. For this, increased voltage and / or current strength is used, as well as a special "smart" process control. The capabilities and features of fast charging may vary depending on the specific implementation of the technology. Most often, accelerated charging implies the possibility of literally 5-10 minutes. extend the battery life of the headphones in the accompanying charging case by at least one hour of additional playback.