Adobe 65009626 User Guide - Page 96

USING SOUNDBOOTH CS4 92 Digital audio glossary F FFT (fast Fourier transform) An algorithm based on the Fourier theory, which allows quick analysis of frequency and amplitude. In Soundbooth, you adjust spectral resolution by specifying different FFT sample sizes. (See "Customize the spectral display" on page 33.) frequency Describes the rate at which a sound wave vibrates, measured in cycles per second, or hertz (Hz). A cycle consists of a single, repeated sequence of pressure changes, from zero pressure, to high pressure, to low pressure, and back to zero. A sound wave's frequency determines its pitch: high frequency equals high pitch, and low frequency equals low pitch. (See also "Waveform measurements" on page 6.) H hertz (Hz) Cycles per second. A unit of measurement that describes the frequency of a sound. (See "frequency" on page 92.) L latency Measures the delay between user input and sound output from a computer. If latency is high, it produces an audible echo during recording, disrupting timing for musicians. To reduce latency, use sound cards with ASIO or Core Audio drivers. limiter A signal processor that prevents audio from clipping. If the input signal exceeds the specified threshold level, the output level remains constant even if the input increases in volume. M mastering The process of finalizing audio for a specific medium, such as the web or an audio CD. Mastering consists of several processing phases, with equalization and compression phases being the most essential. (To master audio in Soundbooth, see "Mastering effect" on page 56.) millisecond (ms) One thousandth of a second. (There are 1000 milliseconds in a second.) miniplug A common name for 1/8-inch plugs and jacks, sometimes known as minijacks. On the most common sound cards, miniplug jacks provide analog audio inputs and outputs. mix (or mix down) To combine multiple audio sources or tracks and output them together. Though mixes are typically output to a stereo pair of channels, they can be directed to any number of channels (for example, one channel for mono, or six channels for surround sound). mono A monophonic signal, which contains only one sound source. N noise gate A special type of expander that reduces or eliminates noise by greatly lowering signal levels that fall below a specified threshold. Noise gates are often configured to totally eliminate background noise during musical pauses. You can also use these gates to silence pauses in speech. noise shaping A technique that shifts the frequency of dithering noise to minimize its audibility. (See also "dithering" on page 91.) normalize To adjust the highest peak of a waveform so it nearly reaches the digital maximum, 0 dBFS, thereby raising or lowering all other peaks accordingly. The Normalize feature in Soundbooth normalizes audio to 0.3 dBFS, avoiding clipping while ensuring optimal volume. Updated 15 July 2009