Glossary

The maximum change in air pressure. Amplitude is universally measured in decibels (dB). The metric is used both to measure the loudness of a sound signal and to mark the maximum cut-off point for analog and digital recording. This cut-off is the maximum level before distortion and is called the 0dB point.

The term commonly used in analog tape recording or tube amplification when a signal goes above the "red" or maximum recording level. Low-level analog distortion, in contrast to digital distortion, enriches a sound with harmonics and compresses an audio signal, raising the level of quieter sounds.

An online tutorial with an accompanying audio track.

The term used to describe a range of frequencies. Often bandwidth determines the range of frequencies being amplified or reduced by an equalizer. Generally, you are never boosting or reducing one single frequency but instead a range of frequencies.

A feature of RealNetworks' RealServer 5.0 that ensures that all users receive the appropriate encoded content for the best audio quality at their available bandwidth, from 28.8 Kbps modems to dual ISDN connections.

A software utility for converting and processing multiple sound files. A batch processor such as Wave Convert Pro (Mac, Windows) or BarbaBatch (Mac) will import an entire folder of audio files, normalize them, perform EQ enhancements, and convert them on the fly to any popular format such as RealAudio.

An application for converting WAV, AIFF, SDII, AU, and standard MIDI files into RMF files. The Beatnik Editor allows you to import unique instruments or sounds to create an entirely new collection of sounds in the Beatnik sound engine.

A plug-in that manages the playback of RMF files within a web browser. The plug-in is available free at the Beatnik web site and is supported by Netscape Navigator 3.0 and higher or Internet Explorer 3.0 and higher on both Macintosh and Windows platforms.

The term used to describe a microphone that captures sound directly in front and in back of the capsule. For example, a bidirectional mic can be used for recording a duet with musicians on both sides of the microphone.

The size of the binary numbers assigned to describe the dynamic value of each sample. The higher the sampling rate and bit-depth, the more accurate the sound reproduction. In particular, higher bit-depths reproduce quieter sounds more accurately.

A microphone that captures sound directly in front of the capsule, providing maximum noise rejection. Cardioid mics are primarily used for live concert vocal recording and amplification because of the pick-up pattern's excellent feedback-rejection characteristics.

A RealAudio 3.0 utility that enables the creation of a binary event file for synchronizing web pages with audio.

A RealMedia feature that allows multiple RealServers to be configured in a cluster to work as a single machine, exceeding the connection load of a single CPU.

An encoding algorithm that compresses and optimizes audio for Internet transmission.

A dynamics processor that evens out and compresses incoming audio signals that vary greatly in dynamic range, such as a singer going from a soft whisper to a resounding scream. A compressor allows for the hottest incoming signal without distortion to your sound card by limiting the sounds that peak above the 0dB distortion point. By reducing the amplitude of the loudest sounds with a compressor, you can increase the overall input level of your microphone to capture a "hotter" or louder signal.

Decibels of sound pressure levels, a unit of measurement for the loudness of sound.

A logarithmic unit of sound loudness, audio power, or audio voltage.

A dynamics processor or plug-in used to reduce sibilance, or the high frequencies that contain excessive hissing or "S" sounds. De-essers are commonly used to clean up voice-over recordings.

Sound wave reflections or echoes that strike the ear drum after 40 milliseconds of the original sound. Delay, as opposed to reverb, can be heard as a second distinct sound or echo.

The term for hard-disk audio recording and editing on a desktop computer as opposed to an outboard tape recording device.

The process of permanently changing or altering the original master file. When a destructive edit is performed, the sound file is permanently altered and then rewritten to disk. In contrast, nondestructive forms of editing never alter or rewrite over the original sound file.

The term applied to sound that has been digitized into binary code. Sound waves are converted to digital code by means of a circuit that assigns a value or binary set of numbers that correspond to the shape of the incoming electrical wave or current.

A recording device for digital stereo mix-downs and mastering. DAT two-track tapes look like miniaturized VHS tapes and are smaller and more affordable than cumbersome and expensive analog tape reels.

The term used to describe a signal that rises over the maximum 0dB point. Digital distortion produces unpleasant noise and unwanted "clicks" and "pops," which are also known as artifacts. Digital encoding, unlike recording to analog tape, cannot quantify signals above 0dB.

A microphone's capability to reject unwanted sounds coming from off-axis directions. Each type of microphone has a particular recording range or pick-up pattern.

The term applied to Shockwave content authored with Macromedia Director. Director Shockwave leverages the Lingo scripting language to directly interact with the operating system and multimedia functionality of a PC, enabling such capabilities as audio fade-ins and fade-outs, volume and panning control, and audio synchronized with animation and mouse rollovers.

An adjective used to describe an original sound or audio signal that has not been processed or enhanced with effects such as reverb and delay.

The process of boosting or reducing the amplitude of particular sound frequencies. All sounds are made up of an overall spectrum of frequencies that are simultaneously resonating. Equalization is used to boost or reduce a range of frequencies within the full sound spectrum.

Short sounds embedded in an interactive movie or web page as opposed to longer streaming audio tracks. Event sounds are triggered by user input and are most commonly used as rollover button sounds.

A type of volume control knob or slider commonly found on mixing boards.

The term used to describe the wailing or piercing sound that results from a signal loop that occurs when an output signal is fed back into its input.

The term used for capturing sounds on location with portable recording equipment, as opposed to studio recording in a controlled environment.

An authoring environment and file format developed originally by FutureWave Software and later by Macromedia for multimedia creation and delivery over the Web. Macromedia Flash has become the de facto standard for full-scale, high-impact web multimedia. Flash features vector animation technology ideally suited for low-bandwidth connections.

The art of providing audio realism to visuals in post production. Foley sounds are often the first sounds added to a film soundtrack and generally include footsteps, sounds of the actors' clothing, and prop movements onscreen such as a closing doors or an object falling to the floor. Foley artists try to emulate the sounds of real life. The term foley artist originally comes from the time when real life actors performed in a recording room making sounds and noises, with various objects, to simulate the sounds of the action on screen.

Rate or speed of a repeating waveform. A sound's frequency determines its pitch. The faster the frequency, which is measured in hertz (Hz) or cycles per second, the higher the pitch.

The range of frequencies that a device can reproduce or record. The human ear has a frequency response of roughly 20 to 20,000 Hz.

The complete range of frequencies audible to the human ear. Frequency spectrum also refers to the range of frequencies present in a particular sound.

The lowest harmonic of a given tone or musical sound. A pitch consists of a dominant frequency, as well as multiples of this frequency. These additional frequencies are the harmonics. It is the number and characteristics of the harmonics that help create timbre.

A MIDI standard developed to alleviate the problem of unpredictable playback of MIDI compositions. General MIDI specifies that certain note numbers or MIDI channels will play the same type of instrument, such as a drum or piano, across various devices or synthesizers.

A machine or dynamics processor that boosts or reduces the amplitude of a range of frequencies. Graphic equalizers generally have sliding levers, known as faders, representing the different ranges of frequencies between 20 and 20,000 Hz -- the normal hearing range of a human.

The term for small, premade sound effects and clips that are built into the Beatnik plug-in.

The multiples of a given fundamental frequency. Harmonics affect the characteristics of a particular sound.

The basic unit for measuring frequency. One hertz is equal to one cycle per second.

An equalization effect that removes all frequencies below a specified point while preserving those that are above the cut-off point. This effect is often used to remove lower bass sounds, such as a rumble of an automobile engine or the sound of a jet plane flying overhead.

An Internet transmission protocol designed for transferring documents, files, and email over the Internet; primarily suited for the transfer of web pages.

The resistance to current flow. Sounds are colored by the material and substances they travel through. A voice projected through a wall will sound different than a voice projected directly into the ear. As sound travels through the dense materials of a wall, the high-frequency energy is absorbed into the wood leaving behind only the lower frequencies. A voice spoken directly into the ear, on the other hand, will produce an unbearably loud sound. Without the impedance of a wall or other sound-absorbing materials, the energy of the higher frequencies of the voice travel straight to the ear drum.

The term applied to integrating sound into a non-linear interactive media format such as a Flash movie or a CD-ROM.

A RealServer feature that allows all users of a network or intranet to listen to a single live stream, making efficient use of network resources. Multicasting, instead of many simultaneous point-to-point connections, delivers a stream to a certain point in the network where it knows other users are requesting the same file.

A cross-platform programming language developed by Sun Microsystems.

A computer network designed to serve a local facility that is no larger than a few square miles.

A thumbnail-sized microphone designed for inconspicuously capturing close-proximity voices. Lavaliere microphones are commonly used for video shoots and TV talk shows where the use of a large microphone on a bulky stand is unacceptable.

A dynamics processor that limits or prevents signals from peaking above a specified amplitude level. A limiter works by compressing all sounds that peak above a specified threshold point. The average levels of your sound files can be raised several dB beyond the regular normalization level by using a limiter to compress the highest volume peaks. Using simple normalization alone to maximize the dynamic range has limitations. Because the normalization process simply calculates the available headroom, you are limited by the proximity of the loudest peak to the maximum cut-off point.

Macromedia Director's proprietary scripting language for creating sophisticated interactive games and presentations.

An Internet file format and suite of software applications that provide a complete end-to-end solution for secure music delivery over the Internet.

A software package specifically designed for audio professionals in film, radio, television, music, and advertising that allows for the secure real-time preview, approval, delivery, and archiving of broadcast-quality audio.

An application that allows users to preview and purchase CD-quality Liquid Tracks on a Macintosh or Windows PC. It also allows you to see album graphics, lyrics, liner notes, and promotions while listening, as well as easily record an actual Red Book audio CD playable on any home, car, or portable stereo system.

An application that lets you publish and host Liquid Tracks on the Web. The Liquid Music Server also includes an SQL database and can even hook into larger, industry-standard SQL databases, such as those from Informix and Oracle.

The process of capturing and converting a live event for broadcasting over the Web.

A type of compression that squeezes or stuffs data into smaller-sized data packets without permanently discarding information. Compared to lossy forms of compression, lossless compression offers superior audio quality but larger file sizes.

A type of compression that intelligently discards data to achieve smaller file sizes. Lossy forms of audio compression, similar to JPEG image compression, permanently discard frequencies above and below specified points by removing "unnecessary" or redundant sound information. The client-side decoder or player then decompresses the compressed file as the audio downloads to a user's computer and fills in the missing information according to the instructions set by the decoding algorithm.

The perception of the strength or weakness of a sound wave resulting from the amount of pressure produced. Sound waves that have more intensity or larger variations in air pressure produce louder sounds. Low-intensity sound waves with smaller fluctuations in air pressure produce quieter sounds. Loudness is not to be confused with amplitude. Loudness refers to the human perception of sound; amplitude refers to quantifiable measurements of air pressure variations.

An equalization effect that allows all the frequencies lower than a specified frequency to pass through unaffected while filtering out everything above the specified frequency cut-off point.

The term used to describe the three-dimensional area or range of a microphone recording capsule. All microphones have a variation of one or more of the following patterns: omnidirectional, bidirectional, cardioid, and shotgun. Certain recording situations call for the use of different pick-up patterns.

A device that boosts or amplifies the inherently weak signal of a microphone for output to a mixer or sound card.

A transducer device that converts air pressure waves into electrical signals.

A language originally developed to connect various electronic music devices. MIDI has since grown into an important compositional language and tool. MIDI contains no sound data but merely describes in the form of a "composer's score" how a device should playback music. MIDI files are ideally suited for web transmission since they are small, text-based "scores" and not actual representations of sound itself.

Software that provides the necessary sound synthesis to generate musical tones for MIDI playback.

A group of people that meet under ISO (the International Standards Organization) to generate standards for digital video and audio compression. The term MPEG also represents a multimedia compression scheme and format.

A new MPEG format for low-bitrate coding of audio-visual presentations. The MPEG-4 standard was designed for a spectrum of new applications, including interactive multimedia communications, videophone, mobile audio-visual communication, multimedia electronic mail, remote sensing, electronic newspapers, interactive multimedia databases, and games. MPEG-4 targets the very low bitrate applications defined loosely as having sampling dimensions up to 176 x 144 x 10 Hz and coded bitrates between 4,800 and 64,000 bits/sec.

A device that connects and routes all the input and output signals from one component to another. Mixing boards also have signal-processing capabilities such as equalization and reverb. Mixers save you from the hassle of patching together different pieces of equipment for common, day-to-day studio tasks.

The process of recording or capturing several simultaneous tracks of audio.

A component of Windows NT Server and Microsoft's Windows Media Technologies. NetShow services include a comprehensive suite of authoring tools and streaming services for delivering audio, video, animations, and other multimedia over the Internet. NetShow presentations are played back with the Windows Media Player, a universal player that plays most local and streamed media file types including NetShow's native file format, Advanced Streaming Format (ASF), as well as MPEG, WAV, AVI, QuickTime, and RealAudio/RealVideo.

The term applied to non-musical sounds that are mainly comprised of random chaotic frequencies at random amplitudes, such as the roar of a crashing wave or the sound of a computer hard drive.

The inherent background noise level in an audio signal. Poor-quality audio equipment produces a higher noise floor.

A form of audio editing that preserves the original sound file and does not permanently change or rewrite over the original master file but instead merely alters its playback. Nondestructive edits become permanent once the final mix is recorded or "bounced" to disk. With nondestructive editing, the original source files are always preserved as separate sound files.

The process of increasing the overall level of a sound file by boosting the loudest peak in the file up to the maximum 0dB point. If you are working with pre-recorded material, you will want to normalize your sound files before converting them to web formats. Normalization maximizes the dynamic range of a sound file, enhances a sound by making it more present or clear, and sets a uniform volume or amplitude level for a group of sound files recorded or mixed at different volume levels.

A device that captures sounds from all angles. This type of mic is commonly used for recording multiple instruments and voices.

The term used to describe the action of placing or mixing sounds in the left or right channels during stereo playback. All mixers feature a pan knob for adjusting the stereo playback parameters of an audio clip.

An equalizer that allows you to specify the bandwidth and range of the frequencies you want to boost or lower. Unlike a graphic equalizer, parametric equalizers feature several knobs for adjusting bandwidth and gain instead of a horizontal row of faders. Parametric equalizers provide greater flexibility for altering specific frequencies.

The sensation of how high or low a sound is perceived. Pitch is determined by a sound's frequency, or rate of repetition. The faster the frequency, which is measured in hertz (Hz) or cycles per second, the higher the pitch. The slower the frequency, the lower the pitch. On home stereo equipment, high-frequency sounds are often referred to as "treble" and low-frequency sounds as "bass." Piercing sounds such as a siren or whistle are composed of extremely rapid vibrations of air molecules. Lower-pitched sounds such as a bass guitar consist of slower vibrating sound waves.

The process of raising or lowering the pitch of a sound file. Use time correction with pitch shifting if you want to preserve the same length and file size as the original sound.

A circular hoop with a thin nylon material that rests directly between the speaker's mouth and the microphone. Pop screens are essential for reducing wind and explosive P's and S's when recording voices.

A term for HTTP streaming from a standard web server as opposed to UDP or RTSP streaming from a dedicated audio server.

Apple Computer's technology that enables the delivery and playback of video, sound, music, 3D, and virtual reality on Macintosh and Windows computers. QuickTime is also the leading video production platform for both Windows and Mac.

A RealNetworks' utility that enables you to compress audio files or input from an audio device into RealMedia clips.

A RealNetworks' format that works in conjunction with the RealSystem 5.0 to enable broadcasting of streaming Flash vector animation synchronized to RealAudio.

The term used to describe media content such as audio or video, encoded into the RealAudio, RealVideo, RealFlash, RealPix, or RealText formats.

A metafile located on your server that connects a web page to your RealAudio, RealVideo, or RealFlash clips. The metafile contains the URL of one or more clips located on the RealServer.

A RealNetworks' application that decodes incoming audio packets that have been compressed with the RealEncoder back into the original audio signal. The RealPlayer features random access controls such as scroll, stop, start, and pause.

The RealPlayer metafile is the same as the RealMedia metafile but used with the RealPlayer plug-in for Netscape and Internet Explorer.

A RealNetworks' utility that enables you to compress and convert video as well as audio files or live input from a video device. RealPublisher is an enhanced version of RealEncoder and offers web publishing features such as automatic HTML page creation and easy uploading of HTML pages to either a standard HTTP web server or a RealNetworks RealServer. RealPublisher is especially useful for creating web pages that display an embedded RealPlayer.

RealNetworks' streaming media delivery system that works in conjunction with a standard web server to stream encoded audio and multimedia content over the Internet.

RealNetworks' streaming media software that allows users, equipped with conventional multimedia PCs and voice-grade telephone lines, to browse, select, and play back streaming multimedia on demand.

Long-playing streaming audio clips placed in a web page.

Rapid sound wave reflections that strike the ear drum within 40 milliseconds of the original sound. If a sound reflects off of a wall that is close to our ears, we hear the reflections or reverb instantly as part of the richness of the original sound wave decay. If a sound bounces off a hard reflective surface that is far away, we hear the reflection as a second distinct sound or echo. This type of reflection is known as "delay."

A hybrid format developed by Headspace that offers the best of MIDI, digital audio, Java, and JavaScript technologies. An RMF file is a small, efficient music file that contains MIDI, sample, and copyright information in a compressed, encrypted form optimized for playback on the Web. RMF offers the universality, convenience, and small file sizes of MIDI, the interactivity of Java, and a playback sound engine that delivers superb audio quality.

The natural ambient background sound in a given environment such as subtle wind outdoors or the distant hum of an indoor generator or fan.

An open, standards-based protocol for multimedia streaming. RTSP supported by RealSystem G2 provides several advantages over UDP transmission, including better support for synchronized media playback.

A value assigned to represent a portion of an electrical waveform.

The number of samples of an electrical waveform taken per second.

A term used to describe Macromedia Director or Flash content that has been converted for delivery over the Web with the Shockwave utility.

A microphone that contains a recording capsule embedded in a long hollow tube. The capsule picks up a highly exaggerated hyper-cardioid pattern of sounds far in front and back of the microphone.

Overemphasized or particularly loud high frequency noise such as the sounds produced when annunciating S's, P's, and T's. Cutting specific higher frequencies can usually lessen the unwanted effect.

The difference in dB between the maximum input signal level and the system noise level that is introduced to the output signal. High fidelity audio equipment has a higher signal-to-noise ratio.

A time code standard for synchronizing audio to visuals set by the Society of Motion Pictures and Television Engineers.

The vibration of air molecules in the atmosphere that can be sensed by the ear. A sound wave is produced by a force that vibrates the surrounding air molecules, such as a stick striking a wooden surface or a guitar string being plucked. As the air molecules are set in motion, they radiate outwards, colliding into other air molecules like a chain of falling dominoes, until they strike the ear drum. Each type of disturbance in the atmosphere produces a distinct pattern of vibrations. These patterns of vibrating air molecules give a sound its unique loudness, pitch, and timbre.

The process of orchestrating all sounds including the dialogue, music score, and sound effects into one cohesive soundtrack. Full-scale film sound design came about in the late 1970s when film producers and directors realized they could put a sound signature on an entire film by hiring one person -- a sound designer -- to orchestrate all the various audio components into one cohesive soundtrack.

The audio accompaniment to film, graphics, or text.

The speed of sound is 770 MPH.

A RealSystem feature that enables you to split and route the audio signal from one RealAudio Server to several other RealServers located at different strategic points across the Internet. By allowing users to connect to the closest RealServer, you ensure better quality and performance.

Professional monitoring speakers that accurately reproduce a "flat" transparent representation of a sound without adding coloration, distortion, noise, or equalization. Home stereo speakers, by contrast, are designed to boost the high and low audio frequencies to provide a richer sound. Unlike home stereo speakers, the goal of reference speakers is to give you not the most pleasant sound, but the most accurate.

A RealSystem G2 technology for dynamic bandwidth allocation for more efficient and reliable streaming. SureStream switches down to a lower bandwidth without rebuffering the clip when a user's Internet connection degrades or, presumably, if the user's bandwidth was misjudged. RealEncoder G2 with SureStream generates one master file that includes several different bandwidth settings.

A protocol that emphasizes the reliable transfer of data between computers. TCP functions much like an error-correction traffic cop methodically directing the flow of data packets to the same destination, while making sure that everything that was sent arrives at the proper address. TCP, as opposed to UDP, resends lost packets.

A term used to describe the point at which a signal rises above a determined amplitude level or threshold setting and a compressor or limiter begins to compress or reduce the signal.

The tone, "color," or texture of a sound. The term timbre encompasses all of the qualities of a sound besides loudness and pitch, such as smooth, rough, hollow, peaceful, mechanical, etc.

The attack and decay (or beginning and ending) characteristics of a sound such as the quiver of a violin bow as it strikes the strings or the brief squawk of a saxophone as the air begins to vibrate the reed.

A protocol that facilitates the rapid transfer of data between computers. UDP, unlike TCP, keeps directing traffic and does not retransmit packets when data is lost or damaged. When a UDP audio packet drops out, the server keeps sending information causing only a brief glitch instead of a huge gap of silence.

A slightly tremulous effect imparted to a vocal or instrumental tone for added warmth or expressiveness by slight and rapid variations in pitch.

An artist who specializes in voice recording. A voice-over artist is generally someone with a nice quality voice, good microphone technique, and previous theatrical or radio experience.

The native audio format for Windows developed by Microsoft and IBM.

The patterns of air pressure variations that move outward from a point of impact. Waveforms are the "substance" of sound.

The discipline of optimizing sound files for Internet delivery. Mastering for the Web is the final optimization process before converting sound files to their respective web formats.

An adjective used to describe a processed audio signal.