#THE SIGNAL PATH SOFTWARE#

The audio signal is received by the computer in a digital stream that is interpreted by a driver, a piece of software that allows two hardware devices to communicate. The audio interface performs analog-to-digital conversion and passes the digital signal to the computer. The audio interface could be an external device or an internal sound card from GSEAV. During the recording session, the microphone, an analog device, receives the audio signal and sends it to the audio interface in analog form. Now letвЂ™s get back to how a recording session works. Figure 5.20 Signal path in digital audio recording This way, multiple processes can appear to be running simultaneously. Under the direction of the operating system, the CPU can give little slots of times to various processes, swapping among these processes very quickly so that it looks like each one is advancing normally. The CPU works hand-in-hand with the operating system, which is the software program that manages which task is currently being worked on, like a conductor conducting an orchestra. The CPU ( central processing unit) is the main hardware workhorse of a computer, doing the actual computation that is required for tasks like accepting audio streams, running application programs, sending data to the hard drive, sending files to the printer, and so forth. As the audio stream makes its way along the signal path, it passes through a variety of hardware and software, including the microphone, audio interface, audio driver, CPU, input and output buffers (which could be hardware or software), and hard drive. LetвЂ™s look at this more closely now, with special attention to the signal path and conversions of the audio stream between analog and digital forms.ДЇigure 5.20 illustrates a recording session where a singer is singing into a microphone and monitoring the recording session with headphones. In Section 5.1.1, we illustrated a typical setup for a computer-based digital audio recording and editing system.

The signal path