In remixing, a person (often a recording engineer or record producer) takes a familiar song, splits it into different parts called tracks, and changes the song's music, instruments, layout, and or vocals to create a new version of the same song. It is called remixing due to mixing being the putting together of all the parts of a song, and remixing being the putting together of the parts of the song differently than the original.
Remixers, that is, people who remix, are musicians who use a variety of tools, primarily electronic, to create the new song versions. Remixing can be simply moving song parts around; it can also be creating new music for an old song lyric. There are two common kinds of remixing: production and mashups. Production remixing uses new instruments with the old song vocal, and mashups use two old songs mixed together to create a new song.
Many electronic music artists (music made with computers or other electronic instruments) use computer software to make new music parts, called "tracks". The music parts contain notes which are arranged with a computer program called a sequencer. The actual notes are played by instruments, usually synthesizers, a type of electronic musical instrument that makes sounds by changing the shape of a sound wave. It is also possible for a remixer to use a drum sample kit, a set of sounds of fake or real drums recorded for use on a computer.
When the remixer has a proper sequence in the sequencer, he or she can then render the audio part, or track. Rendering requires the sequencer to talk to the musical instrument, usually by computer software or a computer-to-computer talking language called MIDI to an actual electronic keyboard. The sequencer tells the instrument which note to play, and then the instrument plays the note. The sequencer writes this note to a music file on the computer.
A mashup is a remixing style in which a remixer takes two songs and mixes them with each other in a clever way to create a new song. Usually, it is the vocal of the song they want to remix with the other musical parts of an older song.
Instead of using a sequencer and a musical instrument, a remixer can use either record-playing turntables or a computer with an audio sequence editor, for example the program named ACID music. He or she also needs an audio editor, a computer program that allows someone to record sounds into a computer as well as cut them down to smaller bits.
Usually, a small bit of the old song is "cut" in an audio editor into a loop, a piece of music that when played on repeat does not have any skips or musical pauses. This loop is usually called a sample in the world of remixing. This sample is then looped (played over and over) in a sequence to create a new sound. The remixer then mixes the vocal of another song over that loop.
It is also possible that a mashup style remixer will take the entire musical part of one song without its vocal - called an instrumental - and take a vocal from another song without the non-voice part - called an acapella, and put them together to create one song.