Artifice is inherent to pop music, but you still need actual talent to pull it off. Katy Perry might not have said anything of much importance Saturday night at the Tacoma Dome, but her real trick was making you not care one bit.

Before a predictable sold-out mix of screaming preteen girls (and their surprisingly enthusiastic parents), Perry opened the “Prismatic” tour with her hit single “Roar,” rising from the depths of the stage enclosed in a cocoon of LED panels. The crowd dutifully provided their own roars as Perry led them in a triumphant sing-along, opening with a moment most artists would kill to close their sets with.

Nearly a year after its release, Katy Perry’s “Prism,” which spawned her biggest single yet, “Roar,” is still in the top quarter of the Billboard 200 album chart. No doubt her Prismatic World Tour, which will fill the Tacoma Dome Saturday, Sept. 13, isn’t hurting those numbers.

Also featuring: the kick-off of country music at the Washington State Fair, an angst-ridden rock concert in the Gorge and the return of one of Seattle hip-hop’s most-beloved groups.

Katy Perry will perform on Sept. 13 at the Tacoma Dome. Tickets, which are not yet on sale, will cost $20.50-$100.50. Perry will be touring 46 cities in support of her platinum album, “Prism.” For more information and updates on when tickets will be available, visit www.katyperry.com.

Katy Perry, ‘Prism’ (Virgin EMI) Effervescent pop queen Katy Perry’s last album, “Teenage Dream” (2010), was a runaway hit, generating five No. 1 singles and placing her giddy singing career on terra firma. Perry’s fourth studio album, “Prism,” will likely be another big winner. “Roar,” a song of empowerment that references her painful, text-message breakup and subsequent…