Comparison Astell&Kern AK70 vs Astell&Kern AK Jr

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).

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.

Sampling frequency of the digital-to-analogue converter installed in the player (see "DAC").

Sample rate and bit depth are two key characteristics of a digital audio signal; the higher they are, the better the sound quality, other things being equal. Without going into technical details, the meaning of this parameter can be described as follows: for normal sound reproduction, it is necessary that the sampling rate of the player's DAC is not lower than that of the file being played. Otherwise, playback will not be possible even if the audio format is natively supported by the player. (The exception is DSD, see "Supports audio formats" for more on that).

Note that most popular audio formats use a sampling rate of 44.1 kHz, and all modern portable players are guaranteed to support it. So this parameter is relevant mainly for Hi-Fi models (see "Type") that work with advanced digital sound formats.

The capacity of the digital-to-analogue converter installed in the player (see "DAC").

Bit depth, along with sampling rate, is one of the key characteristics of a digital audio signal; the higher it is, the better the sound quality, other things being equal. Without going into technical details, in this case, the meaning of this parameter can be described as follows: for normal sound reproduction, it is necessary that the bit depth of the player's DAC be no lower than the bit depth of the reproduced digital sound, otherwise playback will be impossible.

It is worth noting that the bit depth used in most popular music formats like MP3 is supported by all modern players. So this parameter is relevant mainly for Hi-Fi players (see "Type") that work with advanced digital sound standards.

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.

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.

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 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.
<...br> — 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.

— CUE support. The player's ability to recognize and use .cue files. Initially, such files were used as track lists on Audio CDs, they recorded the sequence of tracks, their duration and title; nowadays, albums and compilations are often accompanied by a .cue file, recorded according to the principle “all tracks in a row in one audio file”. If the player supports CUE, then such an audio file can be listened to on it as a set of separate tracks, switching between them as desired — the player will take data from the .cue file about the start 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.

— Lossless formats. Player support for audio formats that use lossless compression. Unlike lossy compression (in the same MP3), with this compression, the sound is not cut, all its details are preserved as much as possible. There are several lossless formats these days, the most popular being FLAC and APE (see "Supports audio formats"); the specific set of standards that the player is compatible with should be clarified separately. However, anyway, this function will be useful to those who appreciate the most complete and reliable sound. In this case, it is worth considering two nuances. Firstly, lossless files ha...ve a fairly large volume — one album can take several hundred megabytes. Secondly, in order to fully appreciate such sound, you will need high-quality headphones, and ideally a Hi-Fi level player (see "Type").

— Formats without compression (uncompressed). Support by the player for audio formats that do not provide 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 work in the digital-to-analogue converter (DAC) mode — when the device receives a digital audio signal from an external source (usually a computer USB port) and outputs analogue sound. 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: own 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 volume of the sound of individual frequency bands, thus changing the overall colour 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. Anyway, such a setting can be useful both for adjusting the sound to your own preferences, and for compensating for the shortcomings of the 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 — Classic, Rock, Pop, etc.

— Support for aptX. Feature found exclusively on Bluetooth models (see the relevant paragraph). aptX technology is designed to improve the quality of the audio signal transmitted over Bluetooth. With a normal connection, without aptX, the data stream is highly compressed and cut off at individual frequencies; this will noticeably degrade the sound quality and may ruin your music listening experience. This feature eliminates this drawback: when using aptX, the data stream is transmitted almost without compression, while maintaining the original quality. Of course, for this, aptX must be supported not only by the player, but also by the device to which the sound is broadcast (headphones, speakers, etc.)

— FM receiver. Built-in tuner for receiving radio broadcasts in the FM band. It is this range that the vast majority of modern music radio stations use, since it allows you to broadcast sound in stereo. However, some player models also support other standards — for example, AM, in which stations of the "conversational" genre are widely represented. To listen to the radio, you usually need to connect headphones — their wire acts as an antenna.

— Recording from FM-receiver. Ability to record radio programs received by the player's own tuner (see above). This feature 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 studio of a radio station, a live call, etc.

— Dictaphone. Ability to work the player in voice recorder mode — to record sound. Usually, 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 come in handy.

— Built-in speaker. 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 note that the capabilities of the built-in speaker are usually quite modest, as a result, the volume and sound quality are low.

— Digital camera. Own digital camera that allows you to use the player to shoot photos and videos. The quality of filming in most cases is not high, but there are exceptions — some models of players in this indicator are not inferior to middle-class smartphones. In addition, the cameras in this case are designed not so much for highly artistic shooting, but for “fixing the moment”. It is also worth noting that the location of the camera may be different. 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 calls. And the most advanced players (usually models with OS, see above) can have a pair of cameras — the main one and the front one.