The software allows a solo musician to play along to a computer-generated accompaniment with adjustable tempo, adjustable key, and a choice of musical styles. Original accompaniment with custom chord progressions and melody lines can also be created. Band-in-a-Box basically provides a 'back-up band' for a musician to play along with. It can also be used to simulate an entire band with or without soloists.
Band-in-a-Box (BIAB) can create a background for almost any chord progression used in Western popular music. It can then play that song back using the user's choice of one of thousands of different background styles. In addition to playing back the users' songs with built-in, additional, or aftermarket styles, users can edit these or create their own styles from scratch or from existing MIDI files. In BIAB, styles refer to musical styles encapsulated in style files (*.STY). There are thousands of styles included with most BIAB installations. Styles can be MIDI only, a combination of MIDI and RealTracks/RealDrums or RealTrack/RealDrums only (called RealStyles). Users can create their own styles in Band-in-a-Box. The simplest method is to create a hybrid style. Another method is to import a style from a MIDI file, Finally, a user can create a style using the StyleMaker. Band-in-a-Box MultiStyles are styles that can have up to 24 substyles; original Band-in-a-Box styles had two substyles, “a” and “b.” These might be used for (a) chorus, and (b) bridge, for example. BIAB also works with programs like Finale, Garritan Personal Orchestra and other similar packages.
Users can play the songs back and vary the key and/or the song's speed independently or change the number of times any section of the song repeats. The program has a Melodist and Soloist feature, allowing users to choose instruments and specify other details regarding the Melodist or Soloist; Band-in-a-Box will then create these tracks based on the users selections. The Melodist and Soloist tracks can be edited note by note in the Notation window. Leadsheets can be printed for each track for a live band to play, or for learning the parts individually for practice.
Songs can be exported as either a MIDI or audio file. Exporting to a MIDI file allows the user to edit the background generated by Band-in-a-Box in a MIDI sequencer, like RealBand or PowerTracks. Songs created in Band-in-a-Box can be burned to a CD or put on to an MP3 player to share with others when saved as audio files.
Band-in-a-Box used only MIDI sounds until 1999 when digital audio was added to the program, letting users record vocals or an instrument directly into their songs. The introduction of audio lead to the creation of the Audio Chord Wizard released with the 2007 version. This is included with Band-in-a-Box and allows users to choose any audio song from their computer and the Audio Chord Wizard will analyze it and produce the chord progression for it.
In November 2006, PG Music released "RealDrums" allowing users to have pre-recorded real drummers 'play along' with their songs in the Band-in-a-Box program. One year later "RealTracks" were introduced providing the same for pianos, bass, guitars as well as soloing instruments such as saxophones, guitars, pedal steel and others. This has been expanded over the years and as of 2012 there were over 200 RealDrums and 800 RealTracks available. RealTracks uses the élastique Pro V2 time stretching and pitch transposition engine by zplane development which allows the pre-recorded live instruments to retain much of their natural sound while the tempo is varied. There are several different versions of the software available; the larger packages are pre-installed on hard drives due to the size of the audio files. The uncompressed RealTracks and RealDrums WAV/AIFF files are also available for lossless audio use.
Alternative auto-accompaniment software are Harmony Assistant and One Man Band.
The following solos were created by Band-in-a-Box without any user interaction (except picking the style from the list).