NEWARK — An arena show, for all the planning that goes into it, is still a tightrope walk — there is nowhere to hide once the lights go up. So when things began to go wrong for Taylor Swift about midway through her Wednesday night concert at the Prudential Center here, the question wasn’t whether she’d sweat, but if it would show.
She’d just begun to perform “Everything Has Changed” with Ed Sheeran, the cheeky British singer-songwriter who is also one of her opening acts, when the sound slowly began to unravel: Ms. Swift melting in one direction; Mr. Sheeran in another; the band, all the way at the other end of the arena, in a third. Technology, the kind that lets performers hear one another in loud rooms, was failing them.