Form factor
—
Tabletop. Models whose housings are designed for self-installation. This may not necessarily be a table, but any suitable flat surface - for example, a shelf. This form factor is not only universal in terms of placement possibilities, but also extensive in the range of available offerings - it covers models from the budget class to the professional rank.
—
Portable. Mobile solutions with basic switching capabilities and a minimum required set of connection connectors. Typically, portable audio interfaces are intended to be used in field, spartan, or cramped environments where equipment portability is at the forefront. Many of these models are designed to work together with a laptop and/or smartphone.
-
Stand up. The housings of such audio interfaces are designed for installation in telecommunications racks: they are sized to fit a standard slot in the rack and a corresponding set of fasteners. The rack-mount form factor is typical for professional solutions designed for use in recording studios, concert halls and other similar places.
—
Internal (built-in). Internal audio interfaces are usually connected to the computer's system bus and integrated into its hardware. In modern realities, embedded solutions are rare - they are inferior to external analogues in terms of mobility, ease of installation and the ability t
...o use on multiple devices. However, models with an internal form factor allow you to exchange data with a computer at the highest possible speeds and with the lowest possible latency rates.
It is also worth noting that some audio interfaces may have a combined design. In particular, the market offers universal models with both desktop installation and rack mounting options.Number of channels
The number of input and output channels that the audio interface is equipped with. See below for more details on each type.
— Input channels. Input (in) channels on audio interfaces designate the number of different audio signals a device can accept for recording overnight. Their number plays a decisive role in multi-channel sound recording, connecting several instruments or vocals at the same time. When choosing an audio interface, consider not only the number of input channels, but also the types of connectors (see “Inputs”).
— Output channels. Output channels output (out) is the number of audio signals that can be sent to other devices or equipment for playback. The outputs of the audio interface can be used to connect to amplifiers, monitors, speaker systems, headphones, etc. A large number of output channels will come in handy when creating sound mixes, multi-channel recording or multitasking in a studio environment. For simpler tasks, it is enough to have from 2 to 4 output channels. When choosing an audio interface, consider not only the number of output channels, but also the types of connectors (see “Outputs”).
Connection
Connection interfaces that the audio interface is equipped with.
-
USB A. Connection via standard USB port. Until recently, this was the most popular interface for external peripherals, found in almost all PCs and laptops. Nowadays, it is often replaced by a USB type C port (see the corresponding paragraph). Most USB A audio interfaces draw power directly from the PC or other host device.
-
USB type B. The connector has a characteristic square shape, noticeably different from the well-known rectangular USB A ports. In audio interfaces, it is used to transmit signals from external sources to a computer for recording and processing.
-
USB type C. A peripheral connector with a symmetrical contact group, which often replaces full-size USB ports on board modern PCs and laptops. Many new models of audio interfaces are being made for this interface. An exception to the rule is individual instances for Thunderbolt. For them, it is Thunderbolt that is indicated, and not USB type C.
-
Thunderbolt v2. Initially, Thunderbolt is a universal connector used primarily in Apple computer equipment. On board audio interfaces it is used as a general peripheral connector (similar to USB). This uses the miniDisplayPort hardware port. The data transfer speed in this version reaches 20 Gbit/s. Recently, the v2 edition has been rep
...laced by the Thunderbolt v3 version (see the corresponding paragraph).
- Thunderbolt v3. A universal interface that is found mainly in Apple technology. In audio interfaces it is used as a general peripheral connector (similar to USB). Specifically, Thunderbolt v3 provides data transfer speeds of up to 40 Gbps and uses a USB type C hardware connector (as opposed to earlier versions based on miniDisplayPort).
- Lightning. A connector used exclusively in Apple portable electronics (since 2012). Accordingly, audio interfaces with such a port are aimed at ease of connection to iPhones and iPads. Note that today there has been a transition from proprietary Lightning to the common USB type C - the latest generations of Apple gadgets are produced with just such a peripheral connection connector.
- mini-USB. A smaller version of the full-size USB interface, created for portable equipment. It is found very rarely in audio interfaces.
- FireWire. Universal connector, also known as IEEE 1394 or i-Link. In terms of functionality, it is analogous to USB, and in some characteristics it even surpasses it. However, FireWare is much less common. Used to connect to computers and some types of specialized audio equipment.
— Dante Dante connectors are used to connect audio interfaces to a network to transmit audio digitally. In this case, a standard Ethernet port (RJ-45) is used for physical access to the network.DAC
Characteristics of the built-in DAC - a digital-to-analog converter for converting digital audio into line-level analog audio, usually in stereo format.
— Bit depth. Bit size of the digital-to-analog converter (DAC) used in the device. In this case, the meaning of this parameter is as follows: the bit depth of the DAC must be no lower than the bit depth of the audio signal with which the converter is planned to be used, otherwise the device will not be able to effectively cope with the conversion. As for specific values, the standard options in modern audio interfaces are
16 bit,
24 bit and
32 bit.
- Sampling frequency. The sampling rate of the digital-to-analog converter (DAC) installed in the audio interface. Let us recall that such a converter is responsible for converting digital audio into an analog audio signal. The paragraph usually indicates the maximum value of the sampling frequency, for which one of the standard values corresponding to a certain sound quality is used (
48 kHz,
96 kHz,
192 kHz).
Total Jack / XLR audio inputs
— Total audio inputs Jack / XLR. The total number of analog audio inputs such as Jack (6.35 mm) and/or XLR (this interface can be combined with a “jack”). Note that such connectors can play the role of both a line input and a microphone or instrument input. For more details, see the relevant paragraphs.
— mini-Jack. The standard 3.5 mm mini-Jack is usually used in audio interfaces as an analog (line) input for two stereo channels, as well as as a microphone audio input (see the corresponding paragraphs).
Microphone
An input jack used to record audio from a microphone, which may transmit low signal levels and requires amplification. It often includes a microphone preamplifier - it amplifies a weak signal to a level that is suitable for recording or processing in an audio interface. The most common types of microphone inputs are:
—
mini-Jack (3.5 mm). The standard mini-Jack audio connector (3.5 mm) provides average signal quality, which is why it is poorly suited for professional tasks such as studio recording. As a result, the “purely microphone” variety of the 3.5 mm jack is relatively rare, but still has a right to exist. It is also worth considering that microphones can use mini-Jack plugs for different numbers of contacts (from 2 to 4).
—
Jack (6.35 mm). The shape and arrangement of contacts of Jack sockets (6.35 mm) are similar to the corresponding varieties of the 3.5 mm standard, but they are larger in size. Due to the larger contact area and less tendency to interference, plugs of this format are found in microphones of all price categories. In addition, a balanced connection is often made through the 6.35 mm jack - a special type of connection used in professional audio equipment that allows signal transmission even over fairly long wires without interference.
-
XLR. In audio equipment, three-pin XLR connectors are most often used to connect a micropho
...ne. XLR provides a reliable and tight connection, and the interface sockets often have locks to secure the plugs. Connection through this connector is also carried out in a balanced way - using three wires instead of two. The peculiarity of this signal transmission is that external interference is filtered, in fact, by the wire itself, which allows you to transmit a high-quality audio signal even with long cable lengths. Often the XLR connector can be combined with Jack (6.35 mm).Instrument
Connectors used to connect musical instruments (acoustic or bass guitars, keyboards, etc.). Most often they are made in the form of 6.35 mm Jack format sockets, but there are other options (see below). The audio signal from pickups has its own specific characteristics, so the instrument input typically features a higher input level and special impedance matching to ensure optimal sound quality.
—
Jack (6.35 mm). Jack sockets (6.35 mm) are most widely used as instrument audio input. They are very large in size, thereby ensuring tighter contact, and support a balanced connection (for transmitting a high-quality signal without interference over fairly long wires). The number of Jack connectors (6.5 mm) usually corresponds to the number of tools that can be simultaneously connected to the device.
-
XLR. A characteristic round connector, often combined with a Jack interface (6.5 mm). XLR is equipped with a locking lock and three contacts (there are other options in terms of quantity, but they are practically not found). The connector is used to transmit an analog signal through a balanced connection, which provides high immunity to interference - sufficient for professional use.
Total Jack/XLR audio outputs
— Total audio outputs Jack / XLR. The total number of analog audio outputs such as Jack (6.35 mm) and/or XLR (this interface can be combined with a “jack”). Note that such connectors can play the role of both the Main output and the linear output. For more details, see the relevant paragraphs.
— mini-Jack. The standard 3.5 mm mini-Jack is usually used in audio interfaces as an analog (line) output for two stereo channels, as well as as an output for connecting headphones (see the corresponding paragraphs).
Line
The type of line output provided in the audio interface design. It outputs a line-level analog audio signal. This interface is mainly used for connecting recording devices, outputting a signal to playback equipment or to an external amplifier. And the types of connectors used for linear output can be as follows:
—
mini-Jack (3.5 mm). A standard socket for the popular mini-Jack plug (3.5 mm), used as a line output. This connector is mainly used to connect some models of active speakers, while two stereo channels are usually output through one mini-Jack (3.5 mm). Note that headphone outputs, which also use a mini-Jack, are considered separately - see the corresponding paragraph.
—
Jack (6.35 mm). A larger analogue of the mini-Jack connector (3.5 mm) for outputting an analog stereo signal. The Jack output provides a more reliable and noise-free connection, making it ideal for professional applications. Effective protection against interference is possible with a balanced connection method. To save space, the 6.35 mm output can be combined with an XLR connector (see the corresponding paragraph). The disadvantage of this design is the impossibility of using both interfaces simultaneously. Jack line outputs (6.35 mm) adhere to the “one channel per connector” principle.
-
XLR. A round three-pin connector for outputting a line-level analog audio signal, oft
...en with a balanced connection type. Transmission is carried out over three wires instead of two, and during it the noise induced on the wire is eliminated. This allows the use of fairly long cables without compromising the “purity” of the signal, making this type of connection excellent for professional audio equipment. XLR is also considered a professional interface, both due to the ability to work with a balanced signal and due to increased reliability: such connectors are often equipped with locks to secure the plugs.
- RCA. Analog linear audio output using RCA connectors - so-called “tulips” (due to the characteristic shape of the plugs). The standard output of this type consists of two connectors - for the left and right stereo channels. Also note that RCA connectors can be used in other output interfaces, but they have their own names.