An artistic voice is the recognizable way a DJ expresses themselves through music. It develops over time through experience, reflection, and consistent decision-making rather than imitation.
It shows up as a collection of habits rather than a single trait. The kind of track you reach for when a floor needs lifting, the transitions you keep returning to, the moods you are drawn to, and the things you never play. On its own not one of those decisions is remarkable. Repeated across enough nights they become the thing people recognise before they know who is behind the decks.
A voice also keeps moving. What you sound like in five years should not be what you sound like now, and the DJs worth following over a long career manage to keep growing without becoming unrecognisable. That is the actual balance: change enough to stay interested in your own sets, stay consistent enough that people know what they came for. See Musical Identity for where a voice starts and Inspiration for how other DJs feed into it without replacing it.