Comparison B&W PX8 vs B&W PX7 S2

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.

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 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.

For full-size headphones, ear pads are often made of genuine leather, leatherette, textile, velor, leatherette, memory foam, as well as their combined variations. In the caste of in-ear headphones, completely different materials are used - the most common are silicone pads, which gently adapt to the individual structure of the auricle, and as an alternative to them, foam ear pads with a porous structure (so-called “sponges”) are offered. Here are some features of commonly used ear pad materials:

- Textiles. Fabric ear pads are usually found in budget headphone models, but sometimes they are also used in the premium segment. The tactile textile ear pads are pleasant to the touch, and they also allow air to pass through well. In terms of acoustic properties, these are completely neutral materials. Note that such ear pads can be made from various types of fabrics (for example, microfiber).

- Leatherette. Artificial leather substitutes are used in headphones of all price categories. In fact, the properties of this material depend on the specific type of leatherette: ear pads made of conventional eco-leather can have excellent “breathing” qualities, while low-grade leatherette often provokes increased sweating of the ears (especially in the hot season).

- Genuine Leather. Genuine leather is a premium product used in corresponding flagship-level...headphone models. Thick leather provides proper sound insulation and deep bass response. At the same time, your ears may sweat when using leather ear pads. To avoid increased sweating, the leather is often made perforated.

— Velor. The most delicate material to the touch with excellent sound-absorbing abilities. Velor ear pads provide good noise insulation, and headphones with them do not cause fatigue even after a long stay on the head. However, the material also has disadvantages: it gets dirty easily, attracts dust and pet hair, and wears out quickly.

- Alcantara. Ear pads made of artificial suede, which are as close as possible in properties and tactile sensations to velor products. However, Alcantara is easier to clean from dirt and lasts much longer. Alcantara ear pads are found in top-level headphones.

- Foam rubber. Foam ear pads are the prerogative of budget over-ear headphones. The fact is that this is a short-lived material that often requires replacement due to its low strength. Partially, special impregnations solve the problem, but foam rubber still retains its structure for a relatively short time.

- Fur. Quite a rare type of material for making ear pads. Headphones with characteristic fur ear pads perform a practical function - they warm the listener’s ears during the cold season.

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.

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.