Comparison Universal Audio Apollo Twin X Duo vs Audient iD22

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 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.

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).

The audio frequency range supported by the device. Most often we are talking about the range of frequencies that a device can produce in an analog audio output signal.

In general, the wider the frequency range, the fuller the sound, the lower the likelihood that the audio interface will “cut off” the upper or lower frequencies. However, it must be taken into account that the human ear is capable of hearing sounds at frequencies from 16 to 22,000 Hz, and the upper limit decreases with age. So from a practical point of view, it makes no sense to provide a wider range in audio technology. And the impressive numbers found in high-end devices are rather a “side effect” of advanced electronic circuits and are given in the specifications mainly for advertising purposes. Also remember that the overall sound quality is affected by many other factors besides frequency range.

— 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).

Input for digital audio signal transmitted via TOSLINK fiber optic cable. The optical interface has the same capabilities as the coaxial input (see the corresponding paragraph) - in particular, it allows you to transmit multi-channel audio. The key difference and main advantage of this connection is its complete insensitivity to electromagnetic interference. On the other hand, fiber optic cable is quite fragile and sensitive to damage - it must be protected from strong pressure and kinks.

The list of inputs described above is not exhaustive: in modern audio interfaces you can find other, more specific connector options. In particular, Reamp, send, return, chain, HDMI, etc. You can find out the specific specifics of such input interfaces from the manufacturer’s documentation.

— 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).

Through the Main outputs it is supposed to transmit signals from the audio interface to external devices for playing and recording sound. In everyday use, there are models with one type of Main connector, as well as with several varieties (for example, Jack (6.35 mm), XLR, RCA, or Jack (6.35 mm) / RCA, or Jack (6.35 mm) / XLR).

— Jack (6.35 mm). Output for transmitting analog audio signal. Structurally similar to the popular mini-Jack, but differs from it in its larger dimensions. As a result, Jack type plugs (6.35 mm) are used primarily in high-end stationary audio equipment. Outputs of this type usually operate on a “one channel per connector” principle (i.e., to transmit stereo sound you will need to use two Jack sockets). Also, this interface often provides a balanced connection - a connection in a special format that allows the use of long wires without compromising the signal quality (due to the suppression of interference in the wire itself). However, the Jack connection (6.35 mm) may also be unbalanced.

- XLR. Another type of output for transmitting an analog signal using a balanced connection. It allows the use of long cable lengths without compromising the quality of data exchange - external interference is absorbed directly in the cable. Often the connector is combined with a Jack interface (6.5 mm). The XLR is equipped with a locking lock and three contacts. A single three-pin an...alog cable can only carry one channel of audio, so a standard XLR output typically consists of two jacks, stereo left and right.

- RCA. Jacks for coaxial cables with characteristic plugs, popularly known as “tulips”. One cable in analog format can transmit one channel of audio. The standard output of this type consists of two connectors - for the left and right stereo channels. On the other hand, RCA does not provide the possibility of a balanced connection, which is why it is inferior to other options in noise immunity, has noticeable limitations on cable length and is poorly suitable for professional use. Nevertheless, “tulips” have become very widespread in entry-level and mid-level stationary audio equipment.