Comparison FiiO M3K vs xDuoo X2

- Audio. MP3 players in the original, most traditional sense are devices designed to play music and other audio. There are models without a display, but many of the audio players are equipped with screens and can work with auxiliary file formats - like TXT for displaying song lyrics or JPG for viewing album covers or even photos. But the player in them is designed to work only with sound and does not allow video playback.

- Media player. This type includes all players that can play video. The specific characteristics of such models may vary significantly - from portable gadgets with 1.5" - 2" displays and support for specific formats to large 4 - 5" devices capable of working with unconverted files. But in any case, if you need a pocket player with the ability not only listen to music, but also watch videos - it’s worth choosing from similar models.

— Hi-Fi player. A specific type of audio player (see above), created with the expectation of maximum quality of reproduced sound. Uses high-quality components and advanced signal processing circuits; Because of this, such devices are an order of magnitude more expensive than conventional audio players, but in terms of sound quality they are comparable to stationary Hi-Fi class systems. It is almost mandatory for such models to support at least one lossless format like FLAC or A...PE; also only in such devices is it possible to work in DAC mode (see “Functions/capabilities”). In addition, the design may provide specialized interfaces - for example, balanced or optical (see “Outputs”). Thanks to all this, devices of this type can be useful both to demanding audiophiles and to those who work professionally with sound.

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 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.

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".