DAC
Model of the digital-to-analogue converter installed in the device.
DAC in this case means the “heart” of the device, the main circuit that directly provides the conversion of digital audio to analogue. The name of the DAC model is given mainly for advertising purposes — as an illustration of the fact that high-quality components are used in the device. In addition, knowing the model, you can find detailed information about a particular DAC; although in fact such a need does not arise often, it may still arise in some specific cases.
Dynamic range
The dynamic range of a transducer is defined as the ratio between the maximum signal level it is capable of delivering and the level of its own noise when a low amplitude signal is applied. Quite simply, this parameter can be described as the difference between the quietest and loudest sound that the device can produce.
The wider the dynamic range, the more advanced the DAC is considered, the better sound it can produce, all other things being equal. The minimum value for modern devices is about 90 dB, in top models this figure can reach 140 dB.
Also note that this parameter is similar in its meaning to the signal-to-noise ratio, however, these characteristics are measured in different ways; see below for more on this.
Coef. harmonic distortion
The coefficient of harmonic distortion produced by the converter during operation.
The lower this indicator, the clearer the sound produced by the device is, the less distortion is introduced into the audio signal. It is impossible to completely avoid such distortions, but it is possible to reduce them to a level that is not perceived by a person. It is believed that the human ear does not hear harmonics, the level of which is 0.5% and below. However, in high-end audio applications, distortion rates can be much lower — 0.005%, 0.001% or even less. This makes quite a practical sense: the distortions from the individual components of the system are summed up, and the lower the harmonic coefficient of each component, the less distortion there will be in the audible sound as a result.
Bluetooth
Support of the Bluetooth wireless technology by the device. The main application of this technology in the DAC is wireless transmission of sound from an external Bluetooth device (smartphone, laptop, etc.) to the converter. Initially, such transmission was associated with a loss of sound quality, but relatively recently the aptX format appeared, allowing audio to be transmitted via Bluetooth without loss in quality. So when choosing a converter with Bluetooth, it would be a good idea to clarify whether it supports aptX (and, of course, this standard must also be supported by the signal source).
In addition to audio transmission, there are other possible uses for Bluetooth, such as using an external gadget as a remote control. However, they are much less common.
Codec support
Initially, the transmission of sound via Bluetooth involves quite strong signal compression, which can greatly spoil the impression when listening to music. To eliminate this drawback, various technologies are used (the most popular of which is the aptX codec, for Apple devices it is AAC). Of course, to use any of the technologies, it must be supported not only by the amplifier, but also by the Bluetooth device with which it is used.
— aptX. Bluetooth codec, created to significantly improve the quality of sound transmitted via Bluetooth. According to the creators, it allows you to achieve quality comparable to Audio CD (16-bit/44.1 kHz). The advantages of aptX are most noticeable when listening to high-quality content, but even on regular MP3 it can provide a noticeable improvement in sound.
— aptX HD. This codec is a further development and improvement of the original aptX technology, allowing to transmit sound in even higher quality — Hi-Res (24-bit/48kHz). According to the creators, this standard allows to achieve signal quality superior to AudioCD, and sound purity comparable to wired connection. The latter is often questioned, but it can be said that in general aptX HD provides very high sound quality. On the other hand, all the advantages of this technology become noticeable only on Hi-Res audio — with a quality of 24-bit/48kHz or higher; otherwise, the quality is limited not so much by the connection features as by the properties of the source files....
— aptX Low Latency. A specific variation of the aptX described above, designed not so much to improve sound quality as 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, a noticeable desynchronization between image and sound may occur. The aptX LL codec eliminates this phenomenon, reducing the delay to 32 ms — such a difference is imperceptible to human perception (although for serious tasks like studio work with sound, it is still too great).
— AAC. A codec used mainly in Apple portable equipment to improve the sound transmitted via Bluetooth. In this sense, it is similar to aptX (see the corresponding points), but is noticeably inferior to it in capabilities: if the sound of aptX is compared with Audio CD, then AAC is at the level of an MP3 file of average quality. However, for listening to the same MP3, this is quite enough, the difference becomes noticeable only on more advanced formats.
— LDAC. Sony's proprietary Bluetooth codec. In terms of bandwidth and potential sound quality, it even surpasses aptX HD, providing indicators at the level of Hi-Res sound 24-bit/96kHz; there is even an opinion that this is the maximum quality that makes sense to provide in wireless headphones — further improvement will simply be imperceptible to the human ear.
More features
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ASIO support. Support for the ASIO audio standard. This feature is relevant when connected to a computer, when the device actually plays the role of an external sound card. ASIO technology is responsible for the interaction between specialized software and audio hardware; at the same time, it provides data transmission with minimal delay, which allows musicians and sound engineers to process sound in real time. This standard is used exclusively in operating systems of the Windows family, interaction with other operating systems is built in other ways (see in particular
"MAC support").
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DSD support. The device supports the DSD standard, a specific digital audio signal standard that uses the so-called. pulse density modulation. The bit depth of such a signal is only 1 bit, but the sampling rate reaches 2822.4 kHz (64 times more than in the Audio CD format). Compared to the more common PCM standards, this format provides higher sound quality, better noise and error immunity, and lower noise levels. In general, DSD is considered a professional standard, and its support is found mainly in high-end equipment.
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MQA support. The device supports the MQA (Master Quality Authenticated) standard, designed to preserve and transmit the original quality of sound recordings in high resolution. The technology was invented by the
...American company Meridian Audio. In fact, MQA improves standard digital audio by minimizing phase problems and pre-ringing/echo modulation effects. The technology uses special compression algorithms that allow high-quality audio files to be packaged into more compact sizes.
— I2S. Device support I2S standard. This is a digital audio format originally developed for "internal use" — for transmitting a signal between individual modules inside audio devices. However, more recently it has also been used for communication between individual components of audio systems. Note that this format does not have its own connector; various types of connectors can be used to receive the I2S signal, including LAN (RJ-45), BNC and even HDMI. In fact, this connector plays the role of another digital audio input. Specifically, the I2S standard, on the one hand, is distinguished by good communication quality and noise immunity, on the other hand, it is relatively rare.
— Thunderbolt. A universal digital connector, in this case used to connect a device to a computer. Such connectors are most widely used in Apple technology; accordingly, almost all devices equipped with them are compatible with Mac (see the relevant paragraph).
— FireWire. Also known as IEEE 1394 or i-Link. A universal connector that is similar in functionality to USB, and even surpasses it in some characteristics, but is much less common. It is used to connect to computers and some types of specialized audio equipment.
— Bluetooth. The device supports Bluetooth wireless technology. The main application of this technology in DACs is the wireless transmission of audio from an external Bluetooth device (smartphone, laptop, etc.) to the converter. Initially, such a transfer was associated with a loss of sound quality, but relatively recently, the aptX format has appeared, which allows you to transfer audio via Bluetooth without loss in quality. So when choosing a transducer with Bluetooth, it doesn't hurt to check if it supports aptX (and, of course, this standard must also be supported by the signal source).
In addition to broadcasting sound, there are other options for using Bluetooth — for example, using an external gadget as a remote control. However, they are much less common.
— Wi-Fi. Wi-Fi technology supported by the device. Recall that this technology is mainly used as a way to wirelessly connect to the Internet and local networks. Accordingly, most models with this feature are actually network players capable of playing content from local networks and/or the Internet. The specific capabilities of these devices may vary, some of them are even capable of working with Internet radio stations and audio streaming services. Also, Wi-Fi can be used for direct communication with other devices such as smartphones or tablets, but such use is practically not found among DACs.
— Connecting an iPod/iPhone. The presence in the device of special tools for working with portable gadgets from Apple — primarily iPod players and iPhone smartphones. Usually, in such models, the possibility of a wired connection through a standard 8-pin Lightning connector is provided. In addition, the software part may include special functions for integration with the "apple" gadget. But the ways of using such a connection can be different. For example, in a DAC (see "Type"), the iPhone or iPod serves as a source of digital audio, which is converted by the converter and output to the speakers. And audio interfaces with this function are actually adapters for various musical instruments: the sound from the instrument is processed by the interface and digitally transmitted to the gadget for recording and further processing using the built-in software.
— Mac support. Compatibility of the device with computers and laptops from Apple running the proprietary Mac OS X operating system. Such computers have their own specific features and requirements for peripherals, so for guaranteed compatibility, you should choose equipment that originally claims Mac support.
— Phantom power. The presence of phantom power in the device. Such a power supply, with a nominal voltage of 48 V, is necessary for the operation of certain types of microphones — in particular, condenser ones. Accordingly, the presence of this function means compatibility with similar types of microphones — an important feature, given that many high-end studio-level microphones are made specifically with condensers. Phantom power is found only among audio interfaces (see "Type").Output voltage (RCA)
The output voltage provided by the device on the RCA outputs.
See below for more details on these outputs. And compatibility with an external amplifier or other analogue audio receiver depends on this indicator: the output voltage of the DAC must not be lower than the input sensitivity of the receiving device, otherwise the latter will not be able to process the sound normally.
Display
The presence in the device of its own display. This is, usually, the simplest single-colour screen, often with segment indicators that display a limited set of characters. Nevertheless, even such a display is capable of providing quite a variety of information, which significantly improves the usability of the device.
Power supply
The power supply provided in the device.
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From the network. Powered by a normal household outlet. This option is suitable for models with any power and functionality, including the most complex and advanced ones. The mobility of devices with such a power supply is noticeably limited by the power cord, but most of them are initially stationary, so this cannot be called a serious drawback.
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From the USB port. Powered by the port that connects the device to a computer or portable gadget. Most often, we are talking about USB, but other connectors can also be implied: for example, there are devices connected to the iPhone / iPad and powered by a standard “apple” 8-Pin Lightning port, models that are powered by FireWire, etc. The main advantage of this option is the independence of the outlets and the absence of extra wires. On the other hand, connection connectors have limited power supply, so this option is only suitable for the most compact solutions with low power consumption.
— From the network / USB port. Devices that can work both from the network and from the USB connector (or other connection connector). See above for more on these types of food; and their combination in one device provides versatility and allows you to choose the method of nutrition that is most convenient in a given situation.
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From the battery. Power
...ed by own battery. The main advantages of such devices are independence from external energy sources and the absence of extra wires. At the same time, battery power has a significant drawback — a limited operating time: after the charge is exhausted, you inevitably have to take a break to charge the battery. And the mentioned advantages in most cases are not critical for DACs and audio interfaces. Therefore, in its pure form, battery power is extremely rare, more often it is combined with a USB or network connection (see below).
— From the network / battery. The ability to work both from the battery and from a conventional outlet. Both types of food are described in more detail above. Here we note that in this case they complement each other, mutually compensating for shortcomings and making the device universal. So, as long as there are sockets nearby, you can use them (many models are even capable of recharging the battery right during operation), and if connecting to the network is impossible or difficult, switch to the battery.
— From the USB port / battery. The ability to work both from the battery and from the USB port (or other connection connector). See above for details on each of these connection types. And their combination is found exclusively in audio interfaces (see "Type"), it makes the device as versatile as possible. Especially such models will be appreciated by those who work with sound on laptops, tablets or other portable equipment: for example, if the laptop works autonomously, without being connected to a power outlet, you can transfer the audio interface to the built-in battery, saving laptop battery power.