On their debut full-length 604, Ladytron prove how apt their name is: their sound mixes evocative vintage synths and plaintive female vocals as it references over two decades' worth of electronica, new wave, and rock (including Roxy Music, whose "Ladytron" is the group's namesake). Like the Commodore Rock EP, 604 balances Ladytron's experimental and pop sides. "Mu-Tron" and "Zmekya" reinterpret Add N to (X)'s noisy, dystopian soundscapes, and the shimmering "CSKA Sofia" sounds like Kraftwerk filtered through Broadcast. However, it's the tightly structured pop songs that set Ladytron apart. Helena Marnie is Ladytron's lovelorn heart and soul, a heartbroken disco diva singing through her tears on "Another Breakfast With You" and "Discotraxx" and a sadder but wiser confidante on "Playgirl." Meanwhile, Mira Aroya's deadpan singing and Bulgarian accent add a touch of Ninotchka-style wit and irony to "Paco!" which parodies a department store's fake cheeriness, and "I'm With the Pilots," a piece of Weimar Republic-era cabaret brought into the 21st century. Marnie and Aroya's vocals blend perfectly on songs like the brooding, witty single "He Took Her to a Movie." But Ladytron's mix of retro songwriting and modern themes is their most interesting, and distinctive, aspect. Set at the airport and the disco, "Jet Age" blends jealousy and sexual ambiguity, asking "Do you want to be her or don't you / Of course you do / But would she be you?" This subversive streak makes the album's synth-pop more progressive — and more satisfying — than its blatantly experimental moments, but either way, 604 is an exciting debut from a group capable of making overused influences sound fresh again.