Paul and Phil Hartnoll may be the most consistent artists in any techno subgenre, which is both a blessing and a curse. For ten years they’ve made one heart-in-your-mouth classic after another: the eternal “Chime,” the awe-kissed “Halcyon + On + On,” the suspenseful “Are We Here?,” even their reworking of the theme to The Saint (though it alarmed their cred-conscious fans). Each of those hits is a variation on an amazingly durable theme: rock-hard beats, flickering synth riffs, and there-and-gone chords, all shining like a glowstick in a blackout. And each, on its own terms, sounds like the ultimate rave anthem, an effect most of the Hartnolls’ early peers have forsaken for “maturity” or some such nonsense. In short, Orbital is a classic singles act–singles as in tunes, a genuine rarity in ravedom. The down side, of course, is that when you stack ’em end to end, those anthems can get a little monotonous. Still, the Hartnolls put on some of the best concerts in techno, moseying around behind stacks of equipment with headset flashlights to guide them and pouring their sonic glitter down like silver. Sunday, 8:15 PM, Congress Theater, 2135 N. Milwaukee; 773-509-4974 or 312-559-1212. MICHAELANGELO MATOS