Learning About File Formats Supported by Logic Express

Logic Express allows you to access any digitally stored audio recordings (audio files) on your hard disks, in the most common Mac, and several other, file formats.

Audio files imported into a Logic Express project can be at any supported bit depth and sample rate. Logic Express supports bit depths of 16, 20, and 24 bits, and sample rates of 44.1, 48, 88.2, 96, 176.4, and 192 kHz. Logic Express can use the file’s sample rate, or can perform a real-time sample rate conversion. See Setting the Project Tempo.

In addition to audio files, Logic Express can also import MIDI and project information.

The following describes all file formats supported by Logic Express:

WAVE and AIFF Files

Wave (WAV) and Audio Interchange File Format (AIFF) audio files are very similar. They can be stored at different bit depths (16 and 24 bit are supported by Logic Express), in mono, stereo, or surround, and at sample rates up to 192 kHz.

Logic Express also supports Broadcast Wave files, which can contain timestamp information. Files that provide timestamp information can be recognized by a clock symbol, shown alongside the audio region name in the Audio Bin.

The file extension of broadcast wave files is .wav, allowing them to be read by any application that supports the standard wave file format. In such programs, the additional Broadcast Wave file information is ignored.

Core Audio Format Files

Core Audio Format (CAF) files are containers that support integer and float PCM formats, A-law, u-law, and a number of others including AAC and the Apple Lossless Audio Codec (ALAC). Unrestricted file sizes are possible, at high sample rates and bit depths.

Sound Designer Files

Sound Designer I and II (SDII) audio files are similar in structure to AIFF files, and can contain timestamped region information. Use of Sound Designer format files can make transfers between Logic Express and Digidesign Pro Tools software more convenient.

MP3, Apple Lossless, and AAC Files

MP3 and AAC files contain compressed audio information. They are usually far smaller than equivalent WAV, AIFF, or SDII files. This reduction in file size is due to different encoding techniques that “throw away” some of the audio information. As a result, MP3 and AAC files do not sound as good as their WAV, AIFF, or SDII audio counterparts, depending on the source audio material.

Apple Lossless files also contain compressed audio information. As the name suggests, the compression used (ALAC) does not discard audio information in the same fashion as MP3 files. The sound of the compressed audio file is identical to the original recording.

Apple Loops

Apple Loops are audio files that contain additional identification information:  time and date, category, mood, key and tempo, amongothers. They also contain a number of transient markers, which break them down into small time slices. The main advantage of Apple Loops audio files is their ability to automatically match the tempo and key of a Logic Express project.

A second Apple Loops file type is also supported by Logic Express. These contain MIDI note information that triggers a musical phrase or riff. The motif will be played, as is, when these types of Apple Loops are added to an audio track. When added to an instrument track in Logic Express, however, the MIDI note information can be edited, as you would with any MIDI region.

ReCycle Files

ReCycle (REX, RCY) files are generated in Propellerhead ReCycle software. These are similar to Apple Loops audio files, in that they contain a number of slices, and match the project tempo. When imported, a small folder that contains several regions—one for each slice—is created. Each of these slice regions can be handled like any audio region. ReCycle files, unlike Apple Loops files, do not follow the project key.

Standard MIDI Files

Standard MIDI files (SMF) are a standard file format used in MIDI sequencers. They can be read and saved in Logic Express. SMFs may contain note, lyric, controller, and SysEx data. They are added to MIDI or software instrument tracks in Logic Express.

Note: Logic Express can also import GarageBand, OMF Interchange, AAF, OpenTL, and XML files. These file types are usually used to exchange projects, however, and are therefore outside the scope of this chapter. Full details on importing these file types can be found in Project and File Interchange.