Mastering is the (nowadays often digital) finishing of a (sound) mix to a constant overall sound. The relationship between all frequencies is listened to and made visible and small sound corrections are made with various aids (such as an equalizer, hardware and software). Furthermore, a compressor and a limiter are usually used to ensure that the whole will sound louder and that quieter parts are not lost. In addition, the order of a music album is definitively determined, the breaks between the songs are added or songs are put together. Also, there is often a reversion from 24 bit to 16 bit at this stage, as the CD is a 16 bit medium and most digital recorders work with many more bits internally. Finally, the mix is made suitable to be played anywhere.
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