Max. memory card size
The maximum size of the memory card that can be used in the player. This parameter is directly related to the card type (see above): each type has its own volume limits. At the same time, the ability to work with capacious media is limited not only by the type of card, but also by the player's hardware. Therefore, many models have a lower capacity limit than the memory card suggests — for example, 128 GB in a model that supports the SDXC format (the theoretical maximum for which is 2 TB).
Note that the reverse situation also occurs — for example, when a device with a maximum capacity of 16 GB only supports microSD cards (theoretical maximum is 4 GB). This usually means that the player can work with newer formats (in our example, at least microSDHC), but for some reason this point is not mentioned in the official specifications (for example, the manufacturer could make a mistake in the documentation).
Frequency range
The range of audio frequencies that the player is capable of reproducing. The wider this range — the more complete the picture of the sound, the less likely that the device will "cut off" part of the sound spectrum. At the same time, when choosing this parameter, several points should be taken into account.
First, the average human ear is capable of hearing sounds from approximately 16 Hz to 20 kHz; deviations from these figures are small, and with age the range narrows even more. In fact, this means that for normal hearing, it is enough just to cover this gap. And the wider boundaries indicated in the characteristics of the player will be more of a marketing ploy than a really significant moment. Secondly, do not forget that the sound quality is determined not only by the range, but also by a number of other characteristics of the player — signal-to-noise ratio, frequency response, etc.; therefore, a wide range by itself does not guarantee a pleasing sound. And thirdly, the features of the audible sound also largely depend on the headphones used and their frequency range: all the advantages of a player with a wide frequency range can come to naught if the frequencies are “cut off” by the headphones.
Signal to noise ratio
The ratio between the level of the useful signal (clear sound) and extraneous noise, given by the player at the output. This parameter directly characterizes the quality of the built-in amplifier: it mainly takes into account the intrinsic noise of electronic circuits, and the higher the signal-to-noise ratio, the less these noises and the clearer the sound.
Note that in the case of players, this characteristic is often not particularly critical: the noise of the amplifier can be lost against the background of ambient sounds, especially in an urban environment, and for such situations even the most modest indicators, at the level of 70 – 80 dB, are enough. At the same time, for Hi-Fi models (see "Type") this moment is one of the most important; in the most advanced devices, the signal-to-noise ratio can exceed 120 dB.
Power
The higher the power, the louder the sound you can get on the headphones, all other things being equal. In addition, higher power allows you to connect "ears" with higher impedance to the device (although there is no hard correlation here, and models with the same output power may have different headphone impedance limits). However, in the case of ordinary (non-Hi-Fi) players, this parameter is more of a reference than practically significant: usually, the power of the amplifier in such models is quite enough to “rock” most consumer-grade headphones. But for Hi-Fi devices (see "Type") models, output power is of key importance: it determines compatibility with high-resistance studio-class "ears". Detailed help on this issue can be found in special sources.
Headphone impedance
The nominal impedance (impedance) of the headphones that the player can handle normally.
Most consumer-grade headphones are 16 or 32 ohm impedance, which is supported by almost all modern players. Therefore, you should pay attention to this parameter only if you plan to use a device with high-quality "ears" of a studio or audiophile class. A characteristic feature of these headphones is high resistance, already in the hundreds of ohms, and not every player is suitable for them.
Also, it will not hurt to clarify the permissible headphone impedance if you are buying a Hi-Fi class device (see "Type"). Some of these models have a fairly high minimum resistance and are not compatible with standard 16 ohm (and sometimes 32 ohm) "ears".
Harmonic distortion coefficient
The coefficient of harmonic distortion produced by the player.
This parameter directly characterizes the amount of distortion introduced by the device into the original sound: the lower the coefficient, the clearer the sound, the less such distortion. It is impossible to completely eliminate them, but they can be reduced to a level that is practically not perceived by a person. So, it is believed that distortions at the level of 0.5% are already invisible even to an experienced listener. At the same time, in modern audio technology, there are also much lower values \u200b\u200b- up to ten thousandths of a percent. In the case of players, such indicators play mainly an advertising role — they are a sign of a high level of the device.
Note that the coefficient of harmonic distortion is indicated mainly for Hi-Fi players (see "Type"), for which the maximum purity of sound is critical; in conventional models, it is of secondary importance.
Audio formats support
Audio file formats that the player is able to work with.
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MP3. The most famous of modern digital audio formats; supported by almost all compact players, the name MP3 has even become a household name for them. Provides so-called. lossy compression, where some of the audio frequencies are lost. However, during compression, the sound is processed in such a way that it "disappears" mainly frequencies, the loss of which is imperceptible to the human ear. As a result, the sound quality can be quite high, and you can clearly distinguish high-quality MP3 from lossless format only on Hi-Fi equipment.
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WAV. Another popular audio standard, originally developed for storing sound on a PC. It can technically be used to store audio in a variety of formats, but is most commonly used for uncompressed audio. Due to this, the sound quality can be quite high, and its processing does not require special computing power. The downside of this is the large volume of audio files — many times more than MP3s.
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WMA. An audio format, at one time specially created for the Windows operating system. By default, it uses lossy compression (although there is also a
lossless version of the WMA codec). WMA is particularly suitable for low bitrates, under such conditions it provides better quality than MP3 and takes up less space. On the other hand, this format is much less popular in high-quality digital audio.
...— AAC. A format developed as a potential successor to MP3. Also provides lossy compression (see above), but allows you to achieve better quality with the same file size; this difference is especially noticeable at low bitrates. Actively promoted by Apple in iPod players; nevertheless, it is noticeably inferior to MP3 in terms of prevalence, although it is supported by a considerable number of players.
— OGG. A lossy compressed digital audio format is one potential alternative to MP3. One of the key features of OGG is that as audio is encoded, the bitrate is constantly changing; at the same time, on fragments where there is no sound, the bitrate drops to almost zero (unlike MP3, where the data stream is constant, including in sections of complete silence). This makes it possible to achieve small file sizes while maintaining sound quality. Also note that the OGG format is open and not limited by patents.
— FLAC. One of the formats that uses lossless audio compression. With this compression, all the details of the original sound are preserved, so lossless formats are especially appreciated by sophisticated music lovers and audiophiles. The reverse side of this quality is large volumes of files. Specifically, FLAC is perhaps the most common of today's lossless formats. This is largely due to the fact that this standard is not particularly demanding on the processing power of the player. Thanks to this, its support can be implemented even in relatively simple and inexpensive players (unlike another popular format — APE, see below). On the other hand, FLAC files are larger than APE files.
— A.P.E. One of the popular lossless audio compression formats. Compared to another common standard — FLAC (see above) — APE allows you to achieve smaller file sizes with the same quality. On the other hand, to play such files, electronics with a fairly high processing power are required, so APE compatibility is relatively rare in compact players.
— DSD. A specific digital audio format using the so-called. sigma-delta modulation (as opposed to pulse code used in most other formats). Such modulation provides a very high sampling rate — 2822.4 kHz; however, it cannot be compared with the usual sampling rate (see above): in this case we are talking about a specific signal format. Its properties are such that DSD support can be provided even if the player's DAC formally has a much lower sampling rate. In general, this format is considered professional, its support is found mainly in Hi-Fi models (see "Type").
— DXD. Professional audio format originally created for editing DSD files (see above) — For technical reasons, original DSD is not well suited for editing. DXD uses a bit depth of 24 bits (8 bits higher than Audio CD format) and a sampling rate of 352.8 kHz (8 times higher than Audio CD). Like the original DSD, it is found mainly in Hi-Fi players.
— AIFF. Audio format developed by Apple for Macs and Macbooks; a kind of "apple" analogue of the WAV described above, also in most cases used for uncompressed audio.
— Audible. Proprietary file format used by the online audiobook store of the same name. One of the features of this format is that file playback is available only if you enter a login and password for the Audible online store; thus, supporting this standard usually means having a client programme to access the store.
This list is not exhaustive, modern players (especially the top category) may support other types of audio files.Features
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CUE support. The player's ability to recognize and use .cue files. Initially, such files were used as lists of tracks on an Audio CD; the sequence of tracks, their duration and name were recorded in them; Nowadays, .cue files often accompany albums and collections recorded on the principle of “all tracks in a row in one audio file.” If the player
supports CUE, then you can listen to such an audio file on it as a set of separate tracks, switching between them at will - the player will take data from the .cue file about the starting point of each track and automatically skip playback. In other words, the listening format will be the same as when playing music in the “one file per track” format.
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Lossless formats. The player supports audio formats that use lossless compression. Unlike lossy compression (including MP3), with this compression the sound is not cut down, all its details are preserved as much as possible. Nowadays, there are several lossless formats, the most popular are FLAC and APE (see “Supports audio formats”); The specific set of standards with which the player is compatible should be clarified separately. However, in any case, this function will be useful to those who value the most complete and reliable sound. It is worth considering two nuances. Firstly,
lossless files are quite large - one album can ta
...ke up several hundred megabytes. Secondly, in order to fully appreciate such sound, you will need high-quality headphones, and ideally a Hi-Fi player (see “Type”).
— Formats without compression (uncompressed). The player supports audio formats that do not require data compression. Most of these standards are professional; they provide very high quality and reliability of sound, but they also take up a lot of space. Examples of uncompressed formats include DSD and DXD (see “Supports Audio”).
— Work in DAC mode. The ability of the player to operate in digital-to-analog converter (DAC) mode - when the device receives a digital audio signal from an external source (usually a computer USB port) and outputs analog audio. This function is found mainly in Hi-Fi models (see “Type”). It will be useful primarily when outputting sound from PCs, laptops or portable gadgets: the native sound cards in such models are often quite “weak”, and when using an external DAC you can achieve much better sound quality.
— Equalizer. This function allows you to adjust the sound volume of individual frequency bands, thus changing the overall color of the sound. Equalizers in modern players can have a different number of bands - from 2 (low and high frequencies) in the simplest models to 8 - 10 in advanced ones. In any case, such a setting can be useful both for adjusting the sound to your own preferences, and for compensating for the shortcomings of connected headphones or speakers - if they “fail” certain frequency bands. In addition, many players have a set of equalizer presets (presets), usually designed for different styles of music - “Classical”, “Rock”, “Pop”, etc.
- FM receiver. Built-in tuner for receiving radio broadcasts in the FM range. It is this range that the vast majority of modern music radio stations use, since it allows broadcasting sound in stereo format. However, some player models also support other standards - for example, AM, in which talk stations are widely represented. To listen to the radio, you usually need to connect headphones - their wire acts as an antenna.
— Recording from an FM receiver. Possibility of recording radio programs received by the player’s own tuner (see above). This function is useful if you want to “save for history” some event from the broadcast - an interesting talk show, a live performance of your favorite band in the radio station’s studio, a live call, etc.
- Dictaphone. The player can operate in voice recorder mode to record sound. Typically, the built-in microphone is used. The general functionality of such a recording is noticeably more modest than in specialized voice recorders, but for simple tasks it may well be useful.
— Built-in speaker. Its own built-in speaker allows you to listen to music without connecting headphones or speakers. In some situations - for example, when watching a movie together from the player screen - this function can be very useful. However, it is worth considering that the capabilities of the built-in speaker are usually quite modest; as a result, the volume and sound quality are low.
- Digital camera. Your own digital camera that allows you to use the player to take photos and videos. The quality of filming in most cases is not high, but there are exceptions - some player models are not inferior to middle-class smartphones in this indicator. In addition, the cameras in this case are intended not so much for highly artistic filming, but for “capturing the moment.” It is also worth noting that the location of the camera may vary. Most often it is installed on the back side, but there are also players with front cameras that allow you to take selfies and use video calling. And the most advanced players (usually models with OS, see above) may have a pair of cameras - main and front.Bluetooth
The player supports
Bluetooth technology.
This technology is designed for direct wireless communication between different devices. There are different ways to implement it in players. The most common option is to broadcast sound to wireless headphones, acoustics or other similar equipment (aptX is highly desirable, see “Features/capabilities”). Other methods of application may also be envisaged - in particular, exchanging files with other devices and remote control (player or from the player). The specific set of additional functions should be clarified separately.
Bluetooth wireless protocols from the 4th revision and newer are relevant today:
- Bluetooth v 4.0. Revision 4.0 introduced a Bluetooth Low Energy (BLE) connection mode with low power 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, which has a positive effect on the stability of the connection.
- Bluetooth v4.1. Development and improvement of Bluetooth 4.0. In terms of players, the key innovation in this version was improved noise immunity when working near 4G (LTE) mobile communication devices (in earlier standards, Bluetooth and LTE signals could overlap, which led to failures).
- Bluetooth v4.2. Further..., after 4.1, development of the Bluetooth standard, which mainly presented a number of general improvements in the reliability and noise immunity of the connection.
- Bluetooth v5.0. 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). The key benefit of these innovations is to improve the overall reliability of communications, increase their range and reduce the number of breaks.
- Bluetooth v5.1. Update to revision v 5.0, in which, in addition to general improvements in the quality and reliability of communication, it became possible to determine the direction from which the Bluetooth signal is coming. Thanks to this, the location of connected devices is determined with centimeter accuracy, which has a positive effect on the quality of the wireless connection.
- 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 v 5.3 came into use 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 v 5.4 was introduced at the beginning of 2023. This edition has 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.