BY JIM DeROGATIS POP MUSIC CRITIC

Plenty of hip indie rockers pay homage to the groundbreaking synth-pop band Kraftwerk, but few come as close as the Liverpool quartet Ladytron to matching the pioneering Germans' mix of innovative electronic soundscapes, ultra-danceable beats and unforgettable pop melodies.

The group recently followed its promising 2001 album "604" with an even stronger disc, "Light & Magic." Now it's touring the States for the first time, with the core members of keyboardists, vocalists and DJs Daniel Hunt, Reuben Wu, Mira Aroyo and Helena Marnie augmented by a bassist and a drummer. I spoke with Marnie by phone from the United Kingdom before the start of the tour, which brings them to Metro tonight.

Q. There hasn't been a whole lot written about Ladytron in the States. Take me through how you came together.

A. Daniel and Reuben kind of knew each other from Liverpool from DJ-ing around, and they had gone to university there. They wanted to do something together and have a band, but they didn't really know what it was going to be like or what shape it would take. Danny met Mira at a club they were DJ-ing at, and they met me very shortly thereafter through mutual friends. I was kind of into the same sort of music, and I was DJ-ing, but I used to live in Oxford. We met up and got along straight away, and I think that was the main thing. We enjoyed what we were doing and we very much took it one step at a time. We'd do a song and try and release it. This was about four years ago, and the first album came out two years ago. We'd been releasing singles for a long time before that.

Q. As strong as "604" was, it seems as if the group took a quantum leap with "Light & Magic."

A. The first one was more of a collection of songs, and some of them had existed for a long time. This one sounds like more of a record because it was done in a much shorter time and it was done to be a record, whereas the first one we were just doing song by song. With this one, we had more of an idea of what we wanted to do, and also, because we got to know each other better over time, all of our personalities come through more. It just seems to work better.

Q. There seems to be a fascination for all of you with the New Wave era and elements of the sound of acts like the Human League and Gary Numan.

A. To be quite honest with you, we're not fascinated by that era very much. We're fascinated by the '60s much more than we are by that era. The whole aesthetic thing is more like late '60s/early '70s, a lot more so than '80s. I think people identify with the '80s because of the synths. They came out in the late '70s or early '80s, and out of those came the New Wave things you're talking about. I love Cabaret Voltaire and stuff like that, but I'm not actually in love with Gary Numan. I like Kraftwerk, but they were a really weird band that was making really, really good pop tunes. Basically, we use old synths because we like the sounds that they make.

Q. The sound is marked by your use of vintage analog synthesizers. Is it difficult traveling with those instruments and converting the currency?

A. It's really difficult traveling, because the synths tend to break down quite a lot. We did a two-week tour of England at the end of last year, and I think we had about three of them dying in the space of two days. They can be fixed, but it's just a bit worrying when you know you're relying on something that's 30 years old and you haven't got another and it's really difficult to find another one of that type. But it's also really difficult when you play because we're not relying on amplifiers, so everything is DI-ed [direct-injected into the sound system], and it's a really complex thing to get it like the records sound live because everything goes through the P.A. There's a lot of technical [crap] like that.

Q. You could use modern samplers to replicate those sounds.

A. Of course we can sample them, but it just doesn't really feel proper. And also when you sample sounds, you're relying on what you've sampled, but when we do stuff live, we're playing around with filters and stuff like that, and you can't do that when you're using samples. It's more organic our way. We bought this mini-Korg thing, which looks like an old vintage instrument and we thought, "OK, we're gonna sample all this stuff down on to it so in case something happens we have it," but it's just not the same thing. If you have a late-'60s Les Paul, you wouldn't be happy with like a [cheap] Encore [guitar], you know what I mean?

Q. Synth pioneer Brian Eno always talked about the beauty of the early analog machines and their ability to surprise you with the turn of every knob.

A. Yeah! They change as well. There's no way that you can get the same sound twice. Sometimes it's irritating, and sometimes you get these really great sounds. You can be really frustrated because you haven't got the time to spend 10 minutes before a song trying to get exactly the right sound, but sometimes it cuts through. Like if there's bit where I want it to sound like a really nasty sort of electric guitar, sometimes it really cuts through and fits really good, but other times you press the key and it's this weird noise that's really irritating. Plus they tend to go out of tune.

Q. So there are some headaches.

A. Yeah, there are a lot of headaches! After the show, we're always going over what went wrong, but hopefully we can cure the headaches.

Q. I remember having a similar discussion with Tim Gane and Laetitia Sadier of Stereolab a decade ago. Do you feel kindred spirit with that band?

A. We've got the same [roadies], the backline people. [Laughs] But yeah, definitely. They kind of approached pop songs in a way we liked. But otherwise, beyond that, they use quite a different format. I think we're maybe a bit simpler in our approach to electronics than they are. I think they're more avant-garde and we're more common and not as clever.

Q. For Ladytron, it seems to be about the song rather than the sound in the end.

A. Yeah, for us it's all about the song. I really liked Stereolab when they were all about the song and not trying to be so clever. And we're all about rocking a bit more as well. I think that kind of comes across more live when we're thrashing about.

Q. You've recorded some amazingly effective tunes--singles such as "Seventeen," "Blue Jeans" and "Playgirl." When do you know you've written a song that works?

A. When you live with the melody in your head before you've actually written it or gotten to record it. And other times, I used to get this when I used to smoke--if I needed a cigarette after a song, I knew I liked it.

Q. Like after sex!

A. [Laughs] Yeah. But now that I'm not smoking, it's kind of really frustrating. But you just know it, I guess. I like all the songs that we've done, but obviously some of them work more as pop hits than others. But you don't think of whether it's going to work or not; you get an idea and you put it down, and if you like it, then you go with it and hopefully it works for other people as well.