A great music score can enhance an otherwise lackluster film or video. Con versely, dialog that is inaudible or distorted can ruin an otherwise well-edited scene. When background audio levels and room acoustic dynamics vary dramatically from shot to shot, viewers unconsciously sense that something is wrong, and their ability to remain connected to the message, story, or characters diminishes exponentially. Well-produced music and audio can't salvage inherently poor footage, but poorly produced music and audio can ruin an otherwise completely enjoyable sequence. Fortunately, Apple's portfolio of professional applications includes some very powerful tools for music composition and audio editing, sweetening, and mixing.
Let's first examine music for music's sake.
Apple's primary applications for music composition on the computer are GarageBand, Logic Express, and Logic Pro.
GarageBand is an incredibly intuitive application ideally suited for musicians who are composing on a computer for the first time. Songs composed in GarageBand can be exported directly to an iTunes playlist in a single step. These same songs can also be used as music beds for videos in iMovie, Final Cut Express, or Final Cut Pro, or to enhance menus in iDVD or DVD Studio Pro. Because GarageBand does not provide a way to synchronize sound to picture, the job of scoring music to picture is best suited to Logic and Soundtrack, both of which we'll review here.
The production workflow for music consists of four discrete processes that tend to fold back on themselves over and over until either the artist/producer is satisfied with the final song, or the production deadline has elapsedhopefully the former before the latter. The workflow includes composition, recording, editing, and mixing. Composition can begin with musical notation as supported in Logic, but often it's part of the recording process, roughing out the melody or beat with Logic's built-in MIDI (Musical Instrument Digital Interface) sequencing and software instruments, considered by many to be among the finest ever developed.
Logic Pro includes a collection of vintage instruments that provide near- perfect emulations of classic instruments like the Hammond B3 organ, software synthesizers that can re-create classic analog textures, and a full-featured stereo sampler that provides the songwriter with access to a myriad of sounds from the countless number of sample libraries currently availablefrom esoteric collections of obscure world instruments to elaborate orchestral libraries. In addition to sound design and electronic composition with MIDI instruments, such as keyboards, Logic is used to record vocals or other real instruments directly to the tracks of each song. Like a multitrack tape recorder, Logic can record multiple audio inputs (vocals, drums, guitars) in real time, whereas GarageBand can only record one input at a time.
Editing involves trimming, timing, and placement of the audio and MIDI tracks in the song. Logic also provides the ability to repair spots in recorded audio files, as well as tools to correct the pitch, length, and timing of MIDI.
The final step in the songwriter's workflow is mixing, and it allows the composer to enhance or "sweeten" the acoustics of each track with a selection of digital signal processing plug-ins including EQ, dynamic compressors, and reverb. The Space Designer reverb plug-in that comes with Logic Pro is based on state-of-the-art convolution technology that actually models the physical characteristics of a room so that the exact acoustics of that room (or any room that's been modeled) can be applied to one or more tracks of audio at any time during the mix. During mixing the producer will adjust individual track levels and pan positions in relation to one another (for example, "cowbell louder and to the left side of the stereo image"). This often involves mixing in a surround sound environment to support the increasingly popular multichannel playback capabilities of DVD and high-definition television.
It's important to note that more and more musicians are finding Logic perfectly suited for live performance as well. Mac OS X includes a number of features that have been specifically designed to please musicians and audio engineers. Chief among them is Core Audio, which essentially removes any cap on the number of audio tracks that the computer can support. Core Audio also supports high-definition audio sampling rates and bit rates up to 96 kHz and beyond. For live performance, Core Audio provides the lowest levels of audio latency in the industry. Latency can best be described as the time it takes to move audio from the input (recording) stage through digital signal processing (DSP) and back out again to be monitored. Any significant delays, and it's like hearing yourself talk to yourself, talk to yourself…you get the idea. Mac OS X now provides levels of audio latency well below 1 millisecond in duration, which has helped Apple to retain its dominant position as the preferred platform for live venues. Musical artists can perform in perfect sync with Logicvocals enhanced with DSP and all tracks mixed in real time on to the waiting ears of the audience.
Soundtrack is a music composition application developed by Apple for musicians and non-musicians alike. Included in Soundtrack is a massive library of over 4,000 audio samples (loops) of sound effects and musical instrumentseverything from the aforementioned cowbell to Motown's finest drum riffs. Apple calls these samples Apple Loops because they offer far more functionality than your standard audio samples. Soundtrack takes advantage of the Velocity Engine of Apple's PowerPC processors by providing the unique ability to preview new loops while simultaneously auditioning other tracks in the timeline. The unparalleled power of this feature becomes evident when you realize that loops are originally sampled (recorded to hard disk) in any number of keys and tempos. To help keep your tracks in tune, Soundtrack can restrict the selection of Apple loops to only those that will work best with other tracks already in the songwithin two semitones of the project key. While it's still possible to combine instruments into something that sounds like it was just dragged in by the cat, Soundtrack provides the necessary tools and technologies to help keep you from going down that path.
Round-trip production between Final Cut Pro and Soundtrack is accomplished primarily through the use of Scoring Markers. The markers are positioned in the Timeline of Final Cut Pro as a reference between the music score and the visual activity (such as a crescendo at a car crash). When a sequence is exported from Final Cut Pro, the scoring markers appear in the timeline of Soundtrack alongside the QuickTime movieconstruction cones on the highway to musical bliss. Apple Loops can be positioned to coincide or snap directly to the markers, but that's not all. Soundtrack allows you to effectively re-time musical cues to the scoring markers by simply dragging the marks to new positions in the timeline to match any additional trim edits made in Final Cut Pro.
Round-trip production between the visual applications in Apple's portfolio and Logic is accomplished primarily through the use of the QuickTime media format. Video movies are exported from Final Cut Pro and Motion and are imported into Logic, where they appear in the audio Timeline as video thumbnails. Perfect sync between picture and sound is maintained via timecodethat dependable timepiece under the hood of QuickTime assets, to keep track of hours, minutes, seconds, and frames. Music is exported from Logic either as discrete tracks or stems (groups of discrete tracks), or as a final mix (stereo or surround) and is imported into Final Cut Pro, where it can be mixed further with location audio and other tracks, like sound effects, replacement dialog, or background ambience.
Producers who recognize the importance of a well-engineered audio mix often ask to be a part of the creative review processenter DVD, the first mass distribution format to dramatically raise the bar on audio quality, with support for Dolby Digital, DTS, even uncompressed PCM audio, with sample rates up to 92 kHz and dynamic range up to 24 bits in length.