Digital Signal Processors (DSP)
Jukebox Jockey has a built in Cross Fader, Silence Detection, Dynamic Amplifier (Dynamic Amp), a Compressor (limiter), and a "ReplayGain" function. These functions will help to ensure quality "jukebox style" playback with no silence, and level volumes between tracks.
Cross Fader
The built in crossfader will fade out the currently playing track and fade in the next track. You can fine tune the cross fader settings at Configuration>Player>Cross Fader. The default settings should be fine for most uses.
Silence Detection
Jukebox Jockey can remove silence in the beginning and end of the tracks. This is helpful in conjunction with the cross fader to create tighter fades and less/no dead air.
Dynamic Amplifier
The dynamic amplifier will adjust the gain of the player either up or down depending on the volume of the track at it's current position.
Compressor
Wikipedia defines clipping as, "Clipping is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. Driving an amplifier into clipping may cause it to output power in excess of its published ratings." Jukebox Jockey's compressor will help prevent clipping.
Replay Gain
Information about Replay Gain can be found at the Replay Gain 1.0 Specification Page.
The ReplayGain specification is a standard which defines an appropriate reference level, explains a way of calculating and representing the ideal replay gain for a given track or album, and provides guidance for players to make the required volume adjustment during playback. The standard also specifies a means to prevent clipping when the calculated replay gain exceeds the limits of digital audio, and it describes how the replay gain information is stored within audio files.
In order to use Replay Gain inside of JJ first you must make sure your audio files have a Replay Gain value stored in the track metadata. Jukebox Jockey does not support the calculation of a Replay Gain value for you (at this time), this should be done with a separate utility. There are various utilities on the internet for scanning your media files and inserting a Replay Gain value into your tracks. Then during the media scanning process, Jukebox Jockey will read and store those values in the database for use during playback.
Replay Gain does NOT change the audio form inside of your files. The process is completely lossless. Instead, the value inserted into the track will tell your player to change the gain to the appropriate levels. There are some methods however that do in fact modify your files and possibly introduce irreversable loss in sound quality. Those methods should be avoided.