With a singer like this, whose low mid-range warmth and upper-spectrum breathiness are essential elements of their character, it makes sense to construct your production around it. Notice here how the piano’s thinned low mids at 0:45 and 1:35 help minimise the risk of muddying the overall mix tonality’s poptastic airiness, as does the staccato envelope of the rhythm synth (first heard at 0:15) that offers the only real low mid-range competition. The bass is also carefully sculpted to provide beef below 200Hz, as well as enough true mid-range to ensure small-speaker compatibility, but with a suckout in the 200-600Hz low mid-range danger zone. At the other end of the spectrum, Bieber all but has the mix to himself. The clock ticks and backbeat are both so transient that they don’t hamper his intelligibility or sheen appreciably, and neither does the beautifully understated shaker (first arriving with the hook at 0:31), on account of its super-smooth tone and comparatively low fader level — enough to significantly enhance the groove, but not an ounce more. All of which leaves a little 1kHz pocket that the rhythm synth and twiddly lead-synth hook can both neatly use to anchor themselves solidly in the balance.