Invert Data

Inverting sound data reverses the polarity of a waveform around its baseline. Inverting a waveform does not change the sound of a file; however, when you mix different sound files, phase cancellation can occur, producing a “hollow” sound. Inverting one of the files can prevent phase cancellation.

In the following example, the red line represents the baseline, and the lower waveform is the inverted image of the upper waveform.

Limiting

Limiting is essentially a hard compressor. Limiting is often used to keep signals from going above a certain level, but can also be applied to create heavily compressed effects. Limiting should only be performed on peaks; if the Threshold level is set too low, heavy distortion will occur.

See also Compression Ratio (audio) on page 346.

Loop

Loops are small audio clips that are designed to create a repeating beat or pattern. Loops are usually one to four measures long.

Low-Pass Filter

A low-pass filter attenuates all frequencies above a cutoff frequency. Low-pass filters can be used as anti-alias filters or for general tonal shaping.

Marker

A marker is an anchored, accessible reference point in a file. Markers are stored in the Regions List and can be used for quick navigation.

Media Control Interface (MCI)

A standard way for Windows programs to communicate with multimedia devices such as sound cards and CD players. If a device has an MCI device driver, it can easily be controlled by most multimedia Windows software.

Microsoft Sound Mapper

The Sound Mapper is a special device that attempts to select the most appropriate sound card (map) on which to play a sound, or it will translate the sound into a format that can be played on your sound card.

Mid-Side recording

Mid-side (MS) recording is a microphone technique in which one mic is pointed directly towards the source to record the center (mid) channel, and the other mic is pointed 90 degrees away from the source to record the stereo image. For proper playback on most systems, MS recordings must be converted to your standard left/right (also called AB) track.

MIDI

See Musical Instrument Device Interface (MIDI) on page 351.

350 APPENDIX E