From Disc to Tape to Disk

Since Victorian inventors first recorded sound onto cylinders and discs, many competing technologies have been used to capture audio and play it back. Disc cutters and wire recorders gave way to magnetic tape as the primary medium after an American serviceman, Jack Mullin, "liberated" two Magnetophon recorders from a Nazi radio station in the final months of World War II. Returning to the USA, Mullin demonstrated the recorders to Bing Crosby in Hollywood. Crosby saw the potential for prerecording his own radio shows and invested in the Ampex company in order that the machines could be produced commercially (see Figure 9-1). (If you don't know who Bing Crosby was, ask your grandmother.) Analog recordings on tape dominated the music industry for decades, ranging in size from gigantic Studer two-inch tape machines down to miniature Nagra eighth-inch machines, used in any spy movie of the period.

Figure 9-1. An Ampex tape recorder from 1965, with its cover removed. Photo by Gregory Maxwell, GNU FDL.

In the 1980s and 90s, digital tape formats including DASH, DAT, and ADAT became popular, only to be replaced in turn by computer-based recorders that use hard disk, CD-R, or Flash memory card storage. A major advantage of computer recording is that the format is file-based, which means any part of the audio can be accessed at random, almost instantaneously. Contrast this to the linear, time-consuming process of having to spool through tape to find the part you want to change. This is why computer-based manipulation of audio and video is sometimes called nonlinear editing.

Recording direct to files on disk can make it faster to transfer material from machine to machine, too. Tapes need to be played back into the digital audio workstation (DAW) before editing, which can take up to an hour each time depending on the length of tape and the speed of the machine. The transfer time adds up if you've got a lot of audio to work on. However, for restoring or remixing older material that exists only on tape or vinyl, this is a valid approach. That's because digital audio editing on a computer offers great control without the generation loss of analog copies or the risks involved in slicing tape with razor blades.

The DAW part of the chain was desk-bound initially, because the hardware requirements for editing audio in real time were beyond the capabilities of the CPUs found in PCs and laptops. Specialized and proprietary digital signal processing (DSP) cards, each costing thousands of dollars, were required to do the job. As CPU capabilities improved about a decade ago, DAW software could be run on the host processor without needing the expensive DSP cards. It then became possible to run some DAW software on a laptop, away from the studio—recordings could be made and edited in the field.

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