A FireWire® audio interface is a means of connecting a computer to a professional audio device. It uses the FireWire® connection protocol, which originally offered higher speeds than universal serial bus (USB) connections. With speed ratings of 400 or 800 megabits per second and a more efficient design than USB, the FireWire® audio interface remains popular, even as USB 3.0 begins to gain popularity in the waning days of 2011.
Also known as iLink or by its technical name as given by the Institute of Electrical and Electronics Engineers (IEEE), IEEE-1394, FireWire® is commonly used for high-speed connections between devices. It has a six wire cable with a rectangular plug with a triangular extrusion on one end. In its usual style, it carries 400 megabits per second of data, while the newer FireWire® 800 standard can carry twice that amount.
Audio devices were originally developed to use the FireWire® audio interface because of the slow transfer speed of USB 1.0. At the time, Macintosh® computers, which were popular in studio settings, supported FireWire® exclusively. As a result, digital audio devices use the FireWire® audio interface to take the data that they have recorded and put it on the computer's hard drive.
Modern professional audio, whether in the studio or in a live setting, is mostly a digital affair. While microphones still capture sound signals, the signal is rapidly converted to a digital format. Once the recording data is digitized, it is in a format where it can be transmitted over FireWire®. The digital signals are then sent through digital mixing and filtering equipment and then to either a hard drive on a computer, for storage and further manipulation, or to a digital-to-analog converter which converts the signals back into analog form for amplification.
As USB has been upgraded to the 480 megabit per second USB 2.0 standard and to the even-faster USB 3.0 standard, that can carry up to 4.8 gigabits per second, professional audio devices have also begun to integrate USB connections. Even with the improvements in USB, FireWire® has a strong installed base of legacy devices. It also has the ability to better allocate its bandwidth between connected devices, preventing connections from running too slow. In addition, FireWire® supports the long cable runs that are common in professional audio setups.