Part II

Audio

Recording,

Editing and

Playback

.

DAT

DATs (digital audiotapes) are capable of audio quality that exceeds what's possible with CDs.

Although the cassette is about two-thirds the size of a standard analog audiocassette, its two-hour capacity is 66 percent greater than a standard 80-minute CD.

Even though DAT has been largely replaced by hard (computer) disk recording, the DAT format is still used to a limited degree in film and television recording.  One of its major advantages is that it incorporates time code that can synchronize audio with other devices.
 

Computer Hard Drives

Today, radio stations and professional production facilities rely primarily on computer hard drives for recording and playing back music, commercials, sound effects, and general audio tracks. Recording audio material on computer hard drives has several advantages.

First, the material can be indexed in an electronic "table of contents" display that makes it easy to find what you need. This index can also list all of the relevant data about the "cuts" (selections) -- durations, artists, etc. Second, by scrolling up or down the index you have (with the help of a mouse or keyboard) instant access to the selections.

Once recorded on a hard drive, there is no wear and tear on the recording medium when audio tracks are repeatedly played. Another advantage is that the selections can't be accidentally misfiled after use. (If you've ever put a CD back in the wrong case, you know the problems this can represent.) And, finally, unlike most CDs, hard drive space can easily be ▲ erased and re-used.

Although hard drives are extremely reliable, they do occasionally "crash," especially after thousands of hours of use or if a major jolt ends up damaging the delicate drive and head mechanism.

Unless anti-virus measures are instituted, and assuming the computer is connected to the Internet or "the outside world," the computer operating system can also be infected with viruses, which can result in a complete loss of recorded material. With these things in mind, critical files and information should always be "backed up" on other recording media.
 

IC and PC Card Recorders

Some audio production is now being done with PC card and IC recorders. These and similar audio and video recorders use a variety of solid-state devices, referred to as ▲flash memory.

These memory cards contain no moving parts and are impervious to shock and temperature changes.

The data in these memory modules can be transferred directly to a computer for editing.

These units typically give you the choice of two basic recording formats: MPEG-2, a compressed data format, and PCM (pulse code modulation) which is an uncompressed digital format. The latter is used with CD players, DAT recorders, and on computer editing programs that use wave (.wav) files.

RAM Audio Recorders

As shown on the right, this new generation of recorders can be a fraction of the size of other types of recorders.

However, unlike recorders with removable media, the stored audio must generally be played back from the unit, itself.

The iPod Era

When iPod-type devices and computers that could "rip" (copy) musical selections from CDs and Internet sources arrived on the scene, consumer audio recording and playback changed in a major way.

Users can assemble hours of their favorite music (up to 2,000 songs) on a computer and transfer it to a pocket-sized, solid-state listening device such as an iPod (on the left) or to one of the new generation cell phones (on the right).

"Podcasts" from TV networks or the Internet  can also be downloaded and listened to or viewed at the user's convenience.  

With the iPod nano (photo on the left) you can watch up to 5 hours of TV shows, music videos, movies, and podcasts.

Although Apple Computer initially popularized these devices, many manufacturers now produce their own versions.

Audio Editing Systems

Audio editing used to require physically cutting and splicing audiotape — an arduous process.

Today, there are numerous computer-based audio editing programs available. Many are shareware that can be downloaded from the Internet.

Shareware can be downloaded and tested, generally for about a month, before the program quits working and you need to pay for it.

Once you pay, you may be given an unlock code that will enable you to use the program for an unlimited time.

Often, minor updates to the program are free; major updates will probably involve an upgrade charge.

In addition to basic editing, audio editing programs offer audio filtering, manipulation, and an endless range of special audio effects.

The audio line above shows how a single channel of sound appears in an audio editor. The vertical red line indicates the cursor (selector) position.

Much as a cursor is used to mark words in a word processing program to make changes as needed, the cursor in an audio time line provides a point of reference for making audio changes.

 

The display above shows how the time lines are integrated into a typical audio editor. Most programs use a computer mouse to drag-and-drop segments and visual effects onto a time-line (the graphical representation of the audio along a time continuum).

The hard drives on computer-based audio editing systems can also store a wide range of sound effects that can be pulled down to a time line to accompany narration and music.

Audio editing in television production is typically handled along with the video on a video editing system. This will be covered in more detail in Module 56.