Fade

A a fade is a gradual increase or decrease in the level of an audio signal. The term can also be used for lighting in theatre, in much the same way.

A recorded song may be gradually reduced to silence at its end (fade-out), or may gradually increase from silence at the beginning (fade-in). For example, the song Bittersweet Symphony by The Verve fades in from the beginning, while the songs "Born to Be Wild" by Steppenwolf, "Boogie Oogie Oogie" by A Taste of Honey, and "Hey Jude" by The Beatles fade out. However, "Born to be Wild" and "Boogie Oogie Oogie" fade out in a matter of seconds, whereas "Hey Jude" takes over 2 minutes to completely fade out. "Goodbye Stranger" by Supertramp takes about a minute to fade out. Fading-out can serve as a recording solution for pieces of music that contain no obvious ending.

The term fade is also used in multi-speaker audio systems to describe the balancing of power between front and rear channels.

The term fade is also used in multi-speaker audio systems to describe the balancing of power between front and rear channels.

Origins and early examples
"Neptune", part of the orchestral suite, The Planets, by Gustav Holst, was the first piece of music to have a fade-out ending.. Holst stipulates that the women's choruses are "to be placed in an adjoining room, the door of which is to be left open until the last bar of the piece, when it is to be slowly and silently closed", and that the final bar (scored for choruses alone) is "to be repeated until the sound is lost in the distance". Although commonplace today, the effect bewitched audiences in the era before widespread recorded sound—after the initial 1918 run-through, Holst's daughter Imogen (in addition to watching the charwomen dancing in the aisles during "Jupiter") remarked that the ending was "unforgettable, with its hidden chorus of women's voices growing fainter and fainter... until the imagination knew no difference between sound and silence".

The technique of ending a spoken or musical recording by fading out the sound goes back to the earliest days of recording. In the era of mechanical (pre-electrical) recording, this could only be achieved by either moving the sound source away from the recording horn, or by gradually reducing the volume at which the performer/s were singing, playing or speaking. With the advent of electrical recording, smooth and controllable fadeout effects could be easily achieved by simply reducing the input volume from the microphones using the fader on the mixing desk.

No single recording can be reliably identified as "the first" to use the technique. In 2003 on the (now-defunct) website Stupid Question, John Buch listed the following recordings as possible contenders:


 * "Bill Haley’s cover version of "Rocket 88" (1951) fades out to indicate the titular car driving away. There are claims that The Beatles’ 'Eight Days a Week' (recorded 1964) was the first song to use the reverse effect -- fade-in. (It also fades out.)"


 * "The earliest such recording anybody could name for me is an 1894 78 rpm record called 'The Spirit of ’76', a narrated musical vignette with martial fife-and-drum that gets louder as it 'nears' the listener and quieter as it 'moves away'."


 * "The fade-out as a simulation of a moving sound source seems to continue right up to 'Rocket 88'. But other examples aren’t so obvious (though fade-out may always imply that the song continues forever and we’re only passing by it for a few minutes)."


 * "The oldest true songs with fade-out pointed out to me by 78 record fans bear no obvious relationship to movement. One is 'Barkin’ Dog' (1919) by the Ted Lewis Jazz Band. Another contender is 'America' (1918), a patriotic piece by the chorus of evangelist Billy Sunday.


 * "By the early 1930s longer songs were being put on both sides of records, with the piece fading out at the end of Side One and fading back in at the beginning of Side Two. Records at the time held only about two to five minutes of music per side. The segue allowed for longer songs (such as Count Basie’s 'Miss Thing'), symphonies and live concert recordings."


 * "However, shorter songs continued to use the fade-out for unclear reasons—for example, Fred Astaire’s movie theme 'Flying Down to Rio' (1933). Even using fade-out as a segue device doesn’t seem obvious, though we certainly take it for granted today."


 * "As a film buff, I have a gut feeling that movies were an influence here. Fade-ins and fade-outs are cinematic devices that begin and end scenes—film language that developed at the same time as these early recordings. The term 'fade-out' itself is of cinematic origin, appearing in print around 1918. And jazz, a favorite of early records, was a popular subject of early movies, too."

Fader
A fader is any device used for fading, especially when it is a knob or button that slides along a track or slot. A knob which rotates is usually not considered a fader, although it is electrically and functionally equivalent. A fader can be either analogue, directly controlling the resistance or impedance to the source (e.g. a Potentiometer); or digital, numerically controlling a digital signal processor (DSP).

Crossfading
A crossfader on a dj mixer essentially functions like two faders connected side-by-side, but in opposite directions. It allows a DJ to fade one source out while fading another source in at the same time. This is extremely useful when beatmatching two phonograph records or compact discs.

The technique of crossfading is also used in audio engineering as a mixing technique, particularly with instrumental solos. A mix engineer will often record two or more takes of a vocal or instrumental part and create a final version which is a composite of the best passages of these takes by crossfading between each track.

In the perfect case the crossfader would keep constant output level. However, there's no standard how this should be achieved. Many DJ equipment manufacturers offer different mixers for different purposes (e.g. scratching, beatmixing, cut mixing, etc.). High-end mixers often have crossfade curve switches allowing the DJ to select the type of crossfade necessary. Experienced DJs are also able to crossfade between tracks using the channel faders.

There are many software applications that feature virtual crossfaders. For instance, burning-software for the recording of audio-cds.