Impedance
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.
Frequency range
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.
Microphone noise canceling
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.Codec support
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.Headphone battery capacity
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).
Weight
The total weight of the headphones; for true wireless models (see "Cable Type"), the weight of each individual earbud is listed.
This parameter is directly related to the design (see above) and some features of the functionality. Thus, the mentioned true wireless devices are very light, their weight
does not exceed 25 g. More traditional in-ears and in-ears can be noticeably heavier,
up to 50g for in-ears and up
to 100g for most in-ears. Overhead models, for the most part, are quite massive: among them there are many models weighing
200 – 250 g,
250 – 300 g and even
more than 300 g. It should be noted that a significant weight for false ears is often not a disadvantage, but an advantage: it allows them to stay on the head more securely, creates an impression of solidity and reliability, and most often does not create significant inconvenience.
In box
Among the equipment, it is worth highlighting
silicone and
polyurethane tips, relevant for in-ear headphones,
additional fixation nozzles and behind-the-
ear arms for better attachment in the ear,
interchangeable ear pads,
additional cable,
dongle,
aircraft adapter,
case / case and
docking station. There are also other accessories. More details about them:
- Silicone tips. Replaceable silicone tips used in in-ear headphones. Usually, several nozzles of different sizes are supplied in the kit, which allows you to adjust the headphones to a specific user. The practical advantages of silicone are softness, durability, general convenience and at the same time low cost.
- Polyurethane nozzles. Replacement tips for in-ear headphones made of foamed polyurethane. This material is somewhat more expensive than silicone, it requires regular cleaning and has a shorter service life - including due to deformation as it wears. On the other hand, polyurethane is ideal in terms of acoustics; it is these tips that are considered the best choice for lovers of in-ear “ears” with high-quality sound.
- Ear hooks. Removable devic
...es designed to additionally secure each earpiece to the ear. Note that such devices should not be confused with behind-the-ear mounts (see above). The main difference is that the arms are used exclusively in some models of in-ear headphones and earbuds as an additional option. In other words, you can wear such headphones without a bow, while the behind-the-ear mount is usually made non-removable and, in principle, you can’t do without it.
— Nozzles of additional fixation. Auxiliary caps for a tighter fit of the in-ear headphones. They are used to provide better fixation of headphones during sports or provide additional volume to users with a large auricle.
- Replaceable ear pads. Comes with interchangeable ear tips. In general, the ear pads are the part with which the headphones come into contact with the listener's ears. In full-size and on-ear headphones, they are soft pads on the inside of the cups.
— Case (case) / cover. Covers are usually called soft rag bags, they protect the "ears" mainly from pollution and take up a minimum of space. Cases are made of hard materials, they are a little more bulky, but they protect well from shock, pressure and contact with sharp objects. In any case, the complete case or case is optimally suited for the headphones and is more convenient than an impromptu protective casing.
- Charging case. Case - a case made of hard material - simultaneously playing the role of a charger. This feature is very popular on true wireless models (see "Cable Type"). The charging case usually has its own battery and the headphones are already charged from this battery; this design provides additional convenience in several moments at once. Firstly, the case, in fact, also performs the function of a power bank - an autonomous power source; the capacity of such a “power bank” may be different, but it is usually enough for several full charges of the “ears” (for more details, see “Capacity of the case”). Secondly, the ability to charge the headphones directly in the case reduces the risk of losing them. Thirdly, the charging procedure itself is quite convenient - just connect the cable to the case.
- Dock station. Stationary stand with the possibility of placing headphones and contacts for charging them. Also, docking stations are often used to transfer the sound track to headphones - they are connected directly to the sound source via a wire, and the sound is transmitted to the ears wirelessly within a certain radius of action.
— Clip for carrying. A clip designed to fasten the wire to a pocket, collar, lapel of clothing, etc. It provides additional convenience: thanks to the clip, the wire does not hang out, the likelihood of touching it with careless movement or catching on the surrounding object is reduced.
- Additional cable. An additional cable provided in addition to the main one may have different features and specializations. So, complete cables can vary in length, connector type, wire type, additional equipment (microphone, volume control), etc. These details should be specified separately in each case. Here, we note that almost all headphones with this configuration have a detachable cable (it makes sense to supplement a non-detachable wire with an extension cable, and it is considered a separate accessory - see below).
- Extension. A type of additional cable designed solely to increase the overall length of the wire. Due to the extension cord, you can adjust the headphones to the specifics of the situation: for example, “build up” the cable if you need to switch from a laptop to a TV or a stationary audio system.
— Airplane adapter. Dedicated headphone adapter for use with modern airliner entertainment systems. In such systems, a special way of connecting headphones is used - through two 3.5 mm jacks (and we are talking about classic "ears", without a microphone). Models with a traditional single 3.5 mm plug can only be connected to this output through an adapter; such adapters may initially be included in the delivery.
- Windproof microphone. Devices in the form of a foam rubber or "shaggy" lining on the headphone microphone capsule. Cut off unnecessary ambient noise and minimize the effect of direct exposure to air currents on the microphone, which can cause interference in speech transmission.
— Dongle. The dongle is used to simplify the organization of connecting wireless headphones to other devices. In fact, this is a radio transmitter (less often a Bluetooth transmitter) that non-contactly broadcasts sound to headphones from a connected device.
This list is not exhaustive and may include other optional items.
