Older high-end studio gear, including audio interfaces, typically has AES3 inputs and outputs on three-pin XLR sockets. The way in which this stream of data is formatted is always the same, and this formatting is the main feature that defines the standard but the physical arrangements used to transmit it can vary. Each AES3 connection can carry a stereo, 24-bit digital audio signal at sample rates of up to 96kHz. One of the best-established standards in the studio world is AES3, sometimes known as AES/EBU. And just as in the world of USB cables, there is a confusing relationship between the type of signal that’s being carried, and the type of connector used to link the sending and receiving device. The ways in which this is done vary depending on how many devices we’re connecting, and in what way.įor reasons that are partly functional and partly historical, you can find several different types of digital input and output on typical audio interfaces. Or, to put it another way, in any studio where devices are connected digitally, one of them needs to be the clock ‘master’, and all the others must be clock ‘slaves’, accepting their timing reference from the master clock. The only way for digital audio to be transmitted successfully from one device to another is for the two devices to share the same clock signal.
Keeping the parts of your digital audio network in sync is very important. For a while, we might be lucky and find that the two clock signals run in sync, but as no two clocks are absolutely identical, one of them eventually will fall slightly behind the other, and the interface will no longer be able to make sense of the data it’s receiving. In this case, the interface receives a stream of samples that are spaced not according to its own clock signal, but to that of the mic preamp. However, consider what happens when we digitally connect a second device, such as a mic preamp with a digital output, to our audio interface. Likewise, there are no clocking issues involved in connecting other hardware in the analogue domain. If we’re just using a single audio interface on its own, it will happily run from its own internal clock. To maintain this regularity, every digital audio device needs a timing reference or ‘clock’. In the case of standard CD-quality audio, there are 44,100 samples per second.
Extend mic cables or word clock cable series#
All of these possibilities can be catered for by a couple of tiny digital connectors.ĭigital audio consists of a series of ‘samples’, measurements of the level of a signal that are taken at regular intervals. One person might find herself wanting an extra eight microphone inputs another might need sixteen line-level inputs to connect a mixing console someone else may wish to add more outputs in order to integrate studio hardware at mixdown.
Extend mic cables or word clock cable free#
Depending on its format, a single digital input can accommodate two, eight, 56 or even 64 channels of audio - even more if we enter the world of audio over IP.ĭigital expansion also leaves the user free to choose the additional input and output types that he or she needs. By contrast, digital expansion formats are incredibly compact. But why do this by a roundabout route? Why not just build more analogue I/O into the interface in the first place?Įvery analogue input and output requires its own electrical circuitry and analogue-to-digital or digital-to-analogue converter, and takes up space on the front or back panel so each one we add increases the cost of the interface and makes it harder to fit everything in.
In other words, what digital inputs and outputs really do is make it possible to add extra analogue inputs and outputs. The role of digital I/O is to allow additional recording hardware to be attached, increasing the capabilities of the audio interface. With a few exceptions, digital inputs can’t be used to directly record musical instruments or microphones their primary purpose is expansion. They also have digital inputs and outputs. Getting To Grips With Digital I/O, Expansion & ClockingĪudio interfaces don’t only have analogue connections.
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