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).
DAC
Model of the digital-to-analogue converter installed in the device.
The DAC is one of the key components of any player: it converts the digital data recorded in the audio file into an analogue audio signal, which is fed through an amplifier to the headphones. The quality of the DAC directly affects how accurately the output sound will match the original signal, as well as whether the player can work with advanced digital signal formats: many of them require high computing power, which is not available in every DAC.
Note that the DAC model is indicated only if it is a high-end converter with above-average sound quality. On the modern market, in particular, DACs from such manufacturers are represented:
AKM,
Cirrus Logic,
ESS Saber,
Texas Instruments,
Wolfson. And players with such equipment usually refer to
Hi-Fi devices(see "Type").
It is also worth mentioning that the number of DACs can be different. The simplest option is
one module for both sound channels, however, there are players equipped with two converters at once — one per channel. This "division of labor" affects the cost, but reduces the load on each individual DAC, which has a positive effect on the quality and reliability of the sound.
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.
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.
—
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.
—
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.
—
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.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.
Battery capacity
The capacity of the battery installed in the player.
Theoretically, a larger battery can provide longer battery life. However, in fact, battery life will depend not only on the capacity of the battery, but also on the power consumption of the player, and it is directly related to the functionality. Therefore, when evaluating battery life, it is better to focus not on battery characteristics, but on the operating time directly stated in the characteristics (see below). And only models with similar characteristics can be compared with each other in terms of battery capacity — for example, media players on Android with approximately the same screen sizes.
Operating time (audio)
The maximum time the player can operate on one battery charge in audio playback mode. You should pay attention to this parameter first of all if you have to use the device for a long time without the ability to recharge the battery. At the same time, note that manufacturers usually indicate an “perfect” operating time: at a constant relatively low volume, without working with the screen and other additional functions that also consume battery. And this means that in fact the battery life of the player may be somewhat lower than stated. Nevertheless, this parameter allows you to fairly accurately assess the suitability of the player for long-term work without recharging, and is also quite suitable for comparing different models with each other.