Not my usual territory, I mainly lurk around shadow phenomena, but a mate who lives in Scottsdale sent me a video he filmed that night and I'm trying to work out if it's the same sighting you're describing.
His footage shows three lights in a loose triangular formation, no sound at all from what he recorded. Steady movement, no deviation. He estimated it was visible for maybe 90 seconds before it just went behind the horizon line.
What I'm trying to establish is whether the craft you saw had any kind of luminosity variation - did the lights pulse or dim at any point, or were they completely static? That detail seems to separate a lot of these triangle sightings into different categories when you start looking at the case history. His lights looked steady to me but the video quality isn't great.
Also curious roughly which direction it was travelling. He was looking roughly northwest from his position.