Hall & Oates were in the middle of recording Private Eyes when Voices suddenly, unexpectedly broke big, with "Kiss on My List" reaching number one not just on the Billboard charts, but in Cashbox and Record World. As the album's producer, Neil Kernon, admits in Ken Sharp's liner notes to the 2004 reissue of the album, everybody knew that the new record would have to do better than Voices, but even if Hall & Oates were under a lot of pressure, they were in the fortunate position of not just having reintroduced their modernized, new wave-influenced blue-eyed soul on their previous record, but they already had much of the material nailed down. In other words, the sound and songs on Private Eyes were essentially conceived when the group was confident of the artistic breakthrough of Voices but not swaggering with the overconfidence of being the biggest pop act in America, and the result is one of their best albums and one of the great mainstream pop albums of the early '80s. Hall & Oates don't repeat the formula of Voices; they expand it, staying grounded in pop-soul but opening up the stylized production, so it sounds both cinematic and sharp. Lots of subtle effects are layered on the voices, guitars, and pianos as they mingle with synthesized instruments, from the keyboard loops that give "Head Above Water" a restless momentum to the drum machine that lends "I Can't Go for That (No Can Do)" a sexy, seductive groove.
Though the production is state of the art for 1981, what keeps Private Eyes from sounding robotic is that it never gets in the way of the kinetic energy of Hall & Oates' touring band, who give the music muscle; they are what keeps the album sounding vibrant 20-plus years after its release, since while elements of the production have dated, it still captures a real band working at a peak. These are the elements that make Private Eyes a sterling example of the sound of mainstream pop circa 1981, but the record was a hit, and has aged well, because both Hall & Oates, along with regular songwriting collaborators Sara and Janna Allen, were at a peak as writers. Yes, Oates' "Mano a Mano" is dorky (arguably in an appealing way), but apart from that there are no duds on the record. "Private Eyes," with its sleek surfaces, widescreen hooks, and unforgettable, handclap-propelled chorus, and "I Can't Go for That (No Can Do)" were the number one hits and the best-known songs here, but the insistent smaller hit "Did It in a Minute" deserved to reach the Top Ten too, as did the album tracks "Head Above Water" and "Looking for a Good Sign," a tribute to the Temptations that is the great forgotten Hall & Oates song. But it isn't just the hits and should-have-been singles; the rest of Private Eyes is filled with strong tunes, such as the reggae-tinged "Tell Me What You Want" and the paranoid vibe of "Some Men," making this a record that improves on Voices in every way, from its sound to its songs. Though they continued their streak of excellent hit singles, Private Eyes was the culmination of the sound they'd been developing since Along the Red Ledge, and it stands as the pinnacle of their time as the biggest pop act in the U.S.A.