Comparison Sennheiser CX 150BT vs Sennheiser CX 6.00 BT

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.

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.

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.

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 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 range of audio frequencies that the headphone's own microphone can normally "hear".

Theoretically, the wider this range, the more advanced and high-quality the microphone is, the closer the sound transmitted by it is to the real one. In fact, extensive frequency coverage is not always required. So, the working range of the human ear is about 16 – 22,000 Hz, and even then not everyone hears its upper part. And human speech usually covers frequencies from 500 Hz to 2 kHz, at least this range is considered quite sufficient for its transmission. So if you need a microphone for simple tasks like voice communication on the Internet or game chat, you can not pay much attention to the frequency range: even in the most modest models, it is more than sufficient for normal speech transmission.

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.

A technology used in Bluetooth models (see "Connection") that allows the headphones to connect to multiple devices at the same time. Thanks to this, you can, for example, listen to music from a laptop, and when a call comes in on a mobile phone, switch the headphones to a conversation. This technology has its own characteristics for different manufacturers, and therefore, if the multipoint function is critical for you, you should separately clarify the details of its operation in the selected model.

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.