Comparison Sennheiser HD 350BT vs Sennheiser HD 4.50 BTNC

— Wired. Headphones connected to the signal source with a cable. Such a connection is highly reliable and noise immunity, gives a minimum of distortion; the headphones themselves turn out to be simple, relatively inexpensive, light, moreover, they do not require their own power supply and have an unlimited operating time. The main disadvantage of this option is the presence of a wire, which limits the range and can create various inconveniences.

— Wireless. Headphones using a Bluetooth, radio, or infrared connection. The most obvious advantage of such models is the absence of a wire, which makes them very convenient to use; and the range is usually at least a few metres. On the other hand, wireless models are noticeably more expensive than wired counterparts, they have a limited operating time and require periodic recharging, and it is more difficult to achieve high sound quality in such devices (there are special technologies like aptX, but they increase the cost even more). In addition, traditional wireless headphones are also heavier and bulkier than wired ones; these shortcomings are devoid of true wireless models, but they have their own nuances.

— Combined. Headphones that allow both of the above connection option...s. The most popular type of such "ears" are wireless models with a detachable cable(see the relevant paragraph); another option is wired headphones with a standard plug, equipped with an adapter for wireless connection. Anyway, having such a model, the user can choose the connection method at his discretion: for example, you can listen to music from a computer via a wire, and when you leave the house, connect your “ears” to your smartphone via Bluetooth. At the same time, the combined devices are not afraid of a dead battery: you can simply switch the “ears” to the cable and continue to use them. The main disadvantage of this type of headphones is the rather high cost.

The specific connection interface provided in the headphones. At the same time, some models may provide several options at once - these are either combined devices (see “Connection type”) or wired headphones equipped with additional adapters.

— micro-Jack (2.5 mm). A wired connector similar to the popular mini-Jack 3.5 mm (see below), but smaller in dimensions. Equipment with such a connection is rare - they are mostly miniature devices, where there is simply no room for a 3.5 mm connector. Accordingly, this interface has not become widespread among headphones: it is almost never found in its pure form; models with such a plug are usually supplemented with an adapter or cable for a mini-Jack.

— mini-Jack(3.5 mm). Perhaps the most popular modern type of audio connector; If a device claims to have a headphone output, most likely it is a 3.5 mm jack. Accordingly, most headphones with a wired connection use this type of connector. It is worth noting that headphones with a microphone designed for such a connection are equipped with a special plug for a combined headphone + microphone audio connector (similar connectors are popular in portable gadgets and laptops). But with a jack intended only for “ears” without a microphone, such a plug may not work correctly. An alternative could be headphones equipped with two separate mini-jack plugs; See below for more details on this option.

— mini-Jack (2 x 3.5 mm).... Models with two 3.5 mm mini-jack plugs. This option is guaranteed to mean that we are not talking about classic headphones, but about a headset with a microphone: one plug is used for headphones, the second for a microphone. Such models are convenient when used with equipment that has separate 3.5 mm jacks for “ears” and a microphone - for example, for a PC.

— Pentaconn (4.4 mm). It is a 5-pin balanced output. Pentaconn uses a larger plug compared to the mini-Jack; its size is 4.4 mm, which is stronger and more reliable than the 3.5 mm connection. Pentaconn's balanced connection makes it possible to work with high-power audio signals. Thanks to this connection, it is possible to transmit a signal over a fairly long distance. Accordingly, such a connector is relevant for headphones of the highest category.

— Jack (6.35 mm). The largest type of Jack-type audio connector found in modern technology. Outputs of this type are found mainly in stationary audio equipment - for portable devices they are too bulky, where it is easier to use a 3.5 mm mini-jack. At the same time, the 6.35 mm connector is considered a more suitable interface for professional and audiophile-grade equipment: it provides a more reliable connection, greater contact density and, accordingly, less likelihood of interference. Therefore, although relatively few headphones (mostly premium solutions) are equipped with their own Jack type connector, many models with a 3.5 mm mini-Jack plug are equipped with an adapter to 6.35 mm.

- XLR. A characteristic round connector with a locking lock and 3 contacts (there are other options for quantity). Typically, it is used to transmit an analog signal over a balanced connection. This connection provides high immunity to interference, typical for professional use; at the same time, the connector itself has quite large dimensions. In view of all this, the presence of XLR is relevant mainly for headphones designed for use with advanced stationary equipment.

— Bluetooth. The most popular wireless connection option in modern headphones. This is due to the fact that built-in Bluetooth modules are available in almost any modern smartphone, tablet or laptop, and appropriate adapters can be produced for devices without this module (for example, a PC). True, the sound quality with a traditional Bluetooth connection is relatively low, but to correct the situation, special technologies like aptX and aptxHD are increasingly being used (see “Codec support”).
It is also worth noting that Bluetooth modules can correspond to different versions (the latest for 2022 are Bluetooth 5.0, Bluetooth 5.1, Bluetooth 5.2, Bluetooth 5.3, Bluetooth 5.4). This point does not affect the sound quality, but it determines a number of additional nuances - communication range and reliability , the ability to work through walls and other obstacles, resistance to interference, etc. In modern “ears” you can find the following versions of Bluetooth:

• Bluetooth v 4.0. An update in which the capabilities of version 3.0 (classic + high-speed Bluetooth) were supplemented with a third format - Bluetooth LE (low energy consumption). This communication standard is intended mainly for transmitting small amounts of information - in particular, service data packets to maintain a connection. At the same time, the creators managed to combine economical energy consumption and a long communication range - it can reach 100 m. This has a positive effect on the stability of the connection.
• Bluetooth v4.1. Development and improvement of Bluetooth 4.0. If we talk specifically about headphones, the key innovation for them in this version is improved noise immunity when working near 4G (LTE) mobile communication devices (in earlier standards, Bluetooth and LTE signals could overlap, which led to failures). So, for use with a 4G smartphone, headphones with Bluetooth support of at least v 4.1 are definitely recommended.
• Bluetooth v4.2. Further, after 4.1, development of the Bluetooth standard, which mainly introduced a number of general improvements in reliability and noise immunity.
• Bluetooth v 5.0. Major Bluetooth update released in 2016. One of the most notable innovations was the introduction of two additional operating modes of Bluetooth LE: an increased speed mode (by reducing the range) and an extended range mode (by reducing the speed). In the case of headphones, the main significance of these innovations is to improve the overall reliability of the connection, increase its range and reduce the number of dropouts.
• Bluetooth v5.1. Update version v 5.0, in which, in addition to general improvements in the quality and reliability of communication, an interesting feature has appeared, such as determining the direction from which the Bluetooth signal is coming. Thanks to this, a smartphone or other gadget that supports this standard is able to determine the location of connected devices with an accuracy of a centimeter; This can be useful, for example, for finding headphones that have disappeared from sight but are still working.
• Bluetooth v5.2. The next update, after 5.1, is Bluetooth 5th generation. The main innovations in this version are a number of security improvements, additional optimization of power consumption in LE mode and a new audio signal format for synchronizing parallel playback on multiple devices.
• Bluetooth v5.3 was introduced at the dawn of 2022. Among the innovations in it, they accelerated the process of negotiating a communication channel between the controller and the device, implemented the function of quickly switching between the operating state in a low duty cycle and a high-speed mode, and improved the throughput and stability of the connection by reducing susceptibility to interference. When unexpected interference occurs in Low Energy mode, the procedure for selecting a communication channel to switch from now on has been accelerated.
• Bluetooth v5.4. introduced at the beginning of 2023, increased the range and speed of data exchange. Also in Bluetooth v 5.4, the energy-saving BLE mode has been improved. This version of the protocol uses new security features to protect data from unauthorized access, has increased connection reliability by selecting the best channel for communication, and prevents connection losses due to interference.

— Radio channel. Wireless connection via radio channel that does not use Bluetooth technology (see above). Such headphones are usually equipped with an adapter that connects to the signal source wired - for example, via USB or mini-Jack 3.5. This connection method is more universal than Bluetooth; it can be used even with devices that do not have wireless modules. In addition, the radio channel provides a long range (often up to several tens of meters), and the sound quality is quite high even without the use of special technologies. The disadvantage of this option is the presence of an adapter, which is not always appropriate: for example, it is more convenient to use Bluetooth headphones with a tablet or smartphone.

- IR channel. Another method of wireless connection, the peculiarity of which is that it does not use radio waves, but infrared radiation. Theoretically, the advantage of such a connection is its resistance to electromagnetic interference, the disadvantage is that it only works in line of sight. In practice, the situation is such that in most cases it is easier to use Bluetooth or a radio channel for a wireless connection. So this option is found exclusively in specialized devices for equipment equipped with their own IR outputs - in particular, among headphones for car monitors.

— USB A. Wired connection to a standard (full-dimensions) USB connector. This option is found exclusively among headphones designed for computers/laptops or gaming consoles. One of its advantages is that sound via USB is transmitted digitally and is processed not by the computer's audio card, but by the built-in headphone converter; such a converter often provides better sound quality than the mentioned audio card. In addition, multi-channel audio can be transmitted via a USB connection - this point will be especially appreciated by gamers. Another advantage is that when using USB headphones, specialized audio outputs remain free, and you can connect other equipment to them - for example, computer speakers or a vibration pad.

- USB C. A relatively new type of USB connector, used in both desktop computers and portable devices - as a successor to microUSB. It is not very different in dimensions, but has a more advanced design - in particular, it is made double-sided, which makes connection easier. Most often complemented by other connection options (they can be either wired or wireless).

- Lightning. A universal connector used in Apple portable devices - iPhone smartphones and iPad tablets - since 2012. Not used by other manufacturers. Accordingly, models with such an interface are designed specifically for Apple technology (primarily iPhone and iPod touch players). This type of connection is especially relevant given the fact that in the latest iPhones the manufacturer has completely abandoned a separate audio output, and the only option for connecting headphones is the Lightning port.

— Branded connector. A connection connector that does not belong to generally accepted standards and is used to a limited extent in equipment from one or several manufacturers. Such connectors are found mainly among headphones for mobile phones. However, due to general standardization, this option has practically disappeared from the scene. Theoretically, the branded connector is also the Lightning described above, but it is separated into a separate category due to the popularity of Apple technology.

The design of the plug provided in the headphones. This parameter is relevant primarily for models with a mini-Jack interface (see "Connection") — the rest of the plugs are made straight in most cases, exceptions are extremely rare.

— Direct. The traditional, most simple and unpretentious option is plugs that do not have any bends. Usually, they are compatible without restrictions with stationary audio equipment, PCs, laptops, etc. But for smartphones and other portable gadgets, this option is not always optimal — it all depends on how the gadget is located in your pocket or case. In some cases — for example, when carrying a smartphone in a regular pants pocket — such a wire can be strongly bent around the plug, which quickly becomes unusable; in such cases it is worth paying attention to L-shaped or curved plugs (see below).

— L-shaped. Plugs angled at 90° in the shape of the letter L. Designed primarily for use with smartphones and other handheld devices: such devices, when worn, can be positioned in such a way that a bent plug is more convenient than a straight one. However, the L-shaped design may also be the best choice for stationary equipment, where the headphone wire approaches the connector at a right angle — for example, this situation is often found in computers and laptops.

— At an angle of 45°. A variation of the L-shaped plug...described above, bent not at a straight line, but at a smaller angle (not necessarily exactly 45 °). It is also designed primarily for pocket equipment, and with such an application, such plugs are considered even more convenient and reliable than traditional L-shaped ones. But for stationary devices, it hardly makes sense to specifically look for a model with a similar connector (although such an application is technically quite possible).

How to connect the cable to the headphones.

— One- sided. In such models, the wire is connected to only one earphone. This option is more comfortable and less prone to tangling, but the headphones must have a headband or neck mount so that there is somewhere to hide the wire that goes to the second ear.

— Bilateral. In such models, a wire is connected to each “ear” separately (the cable for this is usually “forked” closer to the headphones, and sometimes at the plug itself). This is the only option technically available for headphones without a headband or neckband. At the same time, overhead "ears" with a headband can also be made bilateral — in particular, high-end hi-fi and hi-end models, where such a design is provided in order to reduce the influence of wires on each other.

The type of cable provided in the design or delivery of the headphones. Note that this parameter is relevant both for wired or combined models (see “Connection type”), and for some wireless models - in particular, earbuds and in-ear headphones without a mount, where a wire connects one earphone to another.

- Round. The classic round wire is straight, without braiding or other additional accessories. It is inexpensive and in most cases quite practical, which is why it is found in most modern headphones. The disadvantage is that if the thickness is small, the round wire is prone to tangling; therefore, this option is considered not very convenient for compact headphones, such as in-ear or in-ear (see “Design”), which often have to be carried in a pocket or bag.

- Flat. The main advantage of a flat cable is that it does not get tangled as much as a round cable, and if something happens it is much easier to untangle. This is especially important for earbuds and in-ear headphones, which are often rolled up for storage or transport. However, larger overhead models can also be equipped with a flat wire.

— Round, braided. A round wire with an outer braid, usually fabric. See above for details on round wire. And the presence of a braid gives such a cable a number of advantages over the classic one with “bare” insula...tion. Thus, the wire turns out to be more durable, reliable and resistant to kinks and pressure, tangles less, has a solid appearance, and in some models the braiding also provides shielding from external interference. The downside of these advantages is the increased price.

— Spiral. A round cable, coiled into a spring. The main advantages of a spiral wire are that it practically does not tangle and can significantly stretch relative to its original length. The latter is very convenient if, as you use your ears, you have to change the distance to the signal source. The disadvantages of spiral cable are bulkiness and relatively high cost. Therefore, it is often used in mid-range and top-end headphones (including professional models).

- Round, braided. A cable in the form of two wires twisted into a spiral. This option should not be confused with a spiral wire - in this case we are not talking about a spring. This cable is notable primarily for its unusual appearance; For greater originality, the wiring can be made in different colors. It is also somewhat more tangle-resistant than the classic round one, although a lot depends on the thickness. At the same time, individual wires can be noticeably thinner than a solid round wire, which somewhat reduces reliability.

Headphones in which the cable is mounted on a detachable mount and can be detached. A standard 3.5 mm mini-Jack usually acts as a mount, sometimes a USB connector, and the wire itself may not even be included in the package.

This feature is popular primarily among combined models, see "Type of connection": when working in wireless mode, the cable can be disconnected so that it does not hang out in vain. But for purely wired headphones, the main convenience is that, if desired, the “native” wire can be replaced with another one that differs in length, type (see above), connection connector, etc. If desired, you can even keep several detachable cables with different characteristics and change them as needed. In addition, if the detachable wire is damaged, you do not need to buy new headphones or go to the workshop — just buy a new cable.

Among the disadvantages of this option, one can note the risk of losing the wire, as well as a slightly increased likelihood of distortion due to the presence of additional connectors.

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.

Rated headphone sensitivity. Technically, this is the volume at which they sound when a certain standard signal from the amplifier is connected to them. Thus, sensitivity is one of the parameters that determine the overall volume of the headphones: the higher it is, the louder the sound will be with the same input signal level and other things being equal. However, we must not forget that the volume level also depends on the resistance (impedance, see above); moreover, it is worth choosing “ears” for a specific device first by impedance, and only then by sensitivity. In this case, one parameter can be compensated for by another: for example, a model with high resistance and high sensitivity can work even on a relatively weak amplifier.

As for specific figures, headphones with indicators of 100 dB or less are designed mainly for use in a quiet environment (in some similar models, the sensitivity does not exceed 90 dB). For use on the street, in transport and other similar conditions, it is desirable to have more sensitive headphones — about 101 – 105 dB, or even 110 dB. And in some models, this figure can reach 116 – 120 dB. and even more.

It is also worth noting that this parameter is relevant only for a wired connection according to the analogue standard — for example, via a 3.5 mm mini-...jack. When using digital interfaces like USB and wireless channels like Bluetooth, the sound is processed in the built-in headphone converter, and if you plan to mainly use this kind of application, you can not pay much attention to sensitivity.

The coefficient of harmonic distortion produced by this model of headphones.

This parameter determines the amount of non-linear distortion introduced by the headphones into the reproduced sound. The lower it is, the less such distortions, the cleaner and closer to the original sound is. So, an indicator of 1% or more can be considered tolerable at best, from 0.5% to 1% — good, less than 0.5% — excellent (such indicators are acceptable even for monitor headphones), and less than 0.1% — almost perfect.

Note that a low harmonic coefficient in itself does not guarantee high-quality sound — a lot depends on other features of the headphones, primarily the frequency response.