Comparison CMF Buds Pro 2 vs Nothing Ear

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 type of sound emitters installed in the headphones. The type determines the principle of operation of emitters and some features of their design.

— Dynamic. The simplest type of emitters operating on the principle of an electromagnet. Due to the combination of low cost with quite decent performance, it is also the most common, especially among entry-level and mid-range headphones. Such an emitter consists of a magnet, a coil placed in its field, and a membrane attached to the coil. When an alternating current (signal) enters the coil, it begins to vibrate, transmitting vibrations to the membrane and creating sound. From an acoustic point of view, the main advantages of dynamic radiators are a wide frequency range and good volume, the disadvantage is a relatively high probability of distortion, especially with a worn membrane.

— Reinforcing. A peculiar modification of dynamic emitters (see the relevant paragraph), used mainly in high-end in-ear headphones. The basis of the design of such a radiator is a U-shaped metal plate. One of its ends is fixed motionless, the second, movable, is located between the poles of a permanent magnet, and a coil is wound around it (closer to the crossbar), through which the signal current passes. Vibrating under the action of this current, the movable part of the plate transmits vibrations to a rigid membrane, with which it is connected by a thin need...le. This technology allows you to achieve good volume and low distortion with a very small size of the earpiece itself. The disadvantages of reinforcing radiators, in addition to high cost, are uneven frequency response and a relatively narrow frequency range. However, in expensive headphones of this type, several emitters can be provided at once, including on a hybrid basis (see relevant paragraph).

— Hybrid. Hybrid devices are usually called devices that combine dynamic and reinforcing emitters. See above for more details on these varieties; and their combination is used to combine advantages and compensate for disadvantages. Usually, in such headphones there is only one dynamic emitter, it is responsible for low frequencies, and there can be several reinforcing ones, they share the midrange and high frequencies. This allows you to achieve a more uniform frequency response than in purely armature models, but it significantly affects the price.

— Planar. The design of emitters of this type includes two powerful permanent magnets, between which there is a thin film membrane. The shape of the headphones themselves can be either round (orthodynamic emitters) or rectangular (isodynamic). According to the principle of operation, such systems are similar to dynamic ones, with the adjustment for the fact that there is no coil in the design — its role is played by the membrane itself with applied conductive tracks, to which the audio signal is fed. Due to this, distortions associated with the uneven oscillations of the membrane are practically absent; in addition, the sound as a whole is clear and reliable, and the frequency response is uniform. The main disadvantages of planar magnetic headphones are high cost, increased requirements for signal quality, and rather large dimensions. In addition, they are somewhat inferior to dynamic ones in terms of volume and overall frequency range.

— Electrostatic. Like planar-magnetic (see the relevant paragraph), such emitters are designed according to the "sandwich" principle. However, the membrane in them is located not between the magnets, but between the metal grids, and is made of a very thin metallized film. An audio signal is connected to such a system in a special way, and the membrane begins to oscillate due to attraction and repulsion from the grids, creating sound. Electrostatic drivers achieve very high sound quality, low distortion, and high fidelity, but they are bulky, complex, and expensive to use. And it's not just the high cost of the headphones themselves — their operation requires additional matching amplifiers with a voltage range of hundreds or even thousands of volts, and such devices cost a lot, and have the appropriate dimensions.

The number of emitters installed in each individual earphone. Specified only for models with more than one emitter.

The meaning of this feature depends on the type of emitters (see above). So, in hybrid models, by definition, there are several — the frequency range is distributed between them, which has a positive effect on the frequency response. For the same purpose, several reinforcing radiators can be used. And with the traditional dynamic principle of operation, due to several emitters, the effect of surround sound can also be provided (see "Sound").

Anyway, "ears" with numerous emitters, other things being equal, will be more advanced, but also more expensive.

The number of microphones in headphones indicates how many separate microphone capsules are used in the headset for voice transmission and sound processing algorithms. In simple models, there is one microphone, which is sufficient for occasional calls in a quiet room. More advanced TWS, office, and gaming headsets have 2–3 microphones per earbud: some "listen" to the voice, others to the surrounding noise, so the electronics can better eliminate interference and make speech clearer to the listener. A large number of microphones is especially important during conversations outdoors, on public transport, in an open-plan office, and for features like wind noise reduction or precise sound direction detection in gaming models. For instance, a headset with multiple microphones will transmit a voice much better during a conference call or online gaming than basic headphones with one microphone, though it may be slightly more expensive.

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.

The ability to turn off your own headphone microphone using a special button or switch.

This feature is relevant mainly for phone calls, Skype, etc. It is useful in situations where you need to distract from the main conversation and say something that the interlocutor does not need to hear. Disconnecting the microphone is easier and more reliable than covering it with your hand or disconnecting the headphones entirely.

Note that the ability to turn off the microphone may be provided in the communication programme itself (the same Skype, for example). However, again, using the switch on the headphones is more convenient.

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).