The new U2 album is being worked on right now, and is being produced again by the successful "Unforgettable Fire" team of Eno/Lanois. Is that right, we asked The Edge in the group's management offices above their beloved Windmill Lane studio, Dublin?

"Yes, though Eno's just the 'flying' producer on this one: he's coming in at various different stages. We weren't sure whether Eno would want to do it – he's very much caught up with his video-art. I think he had a good time on the last album, he got on with us quite well. But Danny Lanois was the guy we needed, and he was into it which was great. Since he did our last album he's done Peter Gabriel's 'So'; he's probably even better now than he was then."

Having told us all that, Edge then had to slip into another office to check about publicising the re-establishment of the Eno/Lanois/U2 recording partnership. Making Music was the first publication to be told – which is not surprising, seeing how few interviews the group undertake. So why did Edge choose to talk to Making Music, we wondered, as he returned to OK the production announcement?

"I just like the magazine. I thought it was a good idea. I'm not interested generally in guitar-orientated magazines, but this seemed to be a much broader-based thing, which I liked. They either seem to be keyboards or guitars or drums... but Making Music seemed to have a different emphasis. It's not really just gear, it's playing. I like that."

Work officially started on the new LP in January of this year, though in practice it was more like February that things got rolling, and when we spoke in early September the group had completed about 15 backing tracks. You may recall that a lot of the initial work for "Unforgettable Fire" was done with the group recording backing tracks 'live' in various rooms at Dublin's Slane Castle. U2 are aiming to develop that idea for this new album.

"We're going to attempt towards the end of the album to do some actual live recordings," Edge explained, "live vocals with the band, straight down. Maybe not a straight mix, but the performance will go straight to multitrack, everything done live, no overdubs at all. Obviously a certain amount of that becomes conceptual and not necessarily effectual – by that, I mean we're not going to get all hippy about it and say this is the only way to do it. But if it works out, if it's an improvement, great."

They aim, then, to develop the existing backing tracks into songs and then, after all that, to record a separate performance. "And with a choice of different takes," said Edge. "We obviously have to have the song finished: complete lyrics, melodies, backing vocals, basically arranged as we would intend to play it live on stage, and then we record it. How many times have you heard people say boy, this song sounds so much better now than it does on the album? I've heard that said about dozens of groups – Talking Heads, Simple Minds, U2, loads. The performance develops into something which portrays the piece of music in a much better way than the original – the original was maybe too self conscious, too clinically conceived. Whereas on-stage you've done it so many times, you know it so well, that you can virtually ignore everything and concentrate purely on the act of performing it and putting it across. That's what we're aiming to capture on tape. It's sort of ambitious, but that's what we're trying to do."

U2 have always been an ambitious group and, perhaps even more importantly, a spontaneous group. Edge spent quite a bit of our interview underlining his view that the group's musical development is evolutionary rather than intellectual. In other words they let it happen, and try not to think about it too much. But that's certainly not to say they don't have strong opinions about the music. For example, I mentioned that we'd like Edge to show us how to play the guitar part of 'Pride' for our Skill Centre column.

"I don't think I could," he said. "I don't know whether it would work out. You see, the way I play is that things like my treatments and echoes and all that are more important, sometimes, than the actual chord progression I play.

"And I'm not really interested in people playing what I play. I think that's quite harmful, it's the very opposite of what rock 'n' roll is about, for me. What I hope people pick up from U2 is that individuality is the crux of what rock 'n' roll is about. It's not about emulating Jeff Beck or Eric Clapton – if people start with that mentality we'll end up with a lot of people sounding like other people, which is what we've had for ages. In a sense that's what punk did, people like Tom Verlaine said, look, I play like this, it's nothing like anyone else, you don't have to play like anyone else either, just do your own thing. And that's pretty much what we did.

"Every single person who picks up a guitar has the potential to do something unique, and they thwart their potential by trying to sound like other people."

When U2 started playing back in the late 70s they were struck particularly by the New York punk bands then emerging – Edge just mentioned Tom Verlaine of Television, but other ear-prickers included Richard Hell & the Voidoids and earlier activists like Iggy Pop. Was Edge aware that a style was developing in his own playing, even then?

"We were 15, 16, we'd managed to buy a few instruments, couldn't play them, so it was literally in the act of learning how to play our instruments that styles developed. I think we had certain kind of stylistic axioms that weren't conscious – we didn't sort of sit down and write a rule book, this is good, this is bad. But they were understood – the mid 70s 'heavy' approach to guitar is not happening, it's naff, it's something from two or three years ago, we weren't gonna follow it through. Music was coming out of a blues based thing then, that blues scale wasn't being used so much. I don't know the technical details, I'm not musically trained in that respect, but it seems that certain harmonies were not being used. I have heard it said that we use a lot of fifths, and I couldn't argue – I mean I know we do, but it's not a conscious thing."

Elsewhere in this month's issue you may have read Andy Summers explaining how he hit on a similar notion, and at a similar time: in the late 70s, when the Police were also starting out, Summers mentions his deliberate near-avoidance of thirds in chords, and his penchant for fifths and ninths. A parallel here? Edge warmed a little more to the subject.

"Ninths are good, fifths are good, sixths and seventh's," he asserted. "Thirds? Well, I don't like them very much, but I don't avoid them necessarily. Also we work with a tempered tuning, and the actual major third harmony is sharp. That's something I didn't know for a long time, and it's why when heavy metal guitarists are doing crash chords they'll tune the third string flat. It's because the maths of tempered tuning works out so that major thirds are sharp. What I tend to do is leave out any thirds altogether in my chords, I tend to play fifths and root stuff. So in an E chord I'd play Es and Bs. My stripped down chords tend to be octave, root and then a fifth in between, three strings. It tends to be ambiguous, too: it means that it can be major or minor, which is an advantage. It also means that it's fast, three fingers are quick to move about."

Edge says the biggest innovation in his sound came when he discovered echo, originally in the shape of an Electro-Harmonix Memory Man Deluxe bought for £128 in early 1977 from McCullough Pigottin Dublin (which, Edge notes, is now Dublin's Making Music shop), a big investment when U2 had little money. It gave his Explorer's top end more atmosphere and richness, and it helped him sound more like two guitar players.

"Really I just started writing with the echo and it all happened. I found things like its 'modulation' gave me a whole new landscape of guitar sounds to draw from. Parts that would have sounded at best bland without the echo suddenly sounded amazing, and obviously it totally influenced how I played on the first album, 'Boy'. It was like Stuart Adamson once said that he was transporting his H/H combo around, and it fell down this flight of stairs and some bits fell out the back, and when he switched it on the next day it sounded different but much better, and that was the H/H combo he used on all the early Skids stuff. And I thought well, in a funny way that's kind of what happened with the echo – whatever it did, I just liked the sound, it just sounded great to me."

But a lot can happen in ten years. What's the basic set-up Edge is using on the current album sessions, we asked? Trustiest amp is still his Vox AC30 ("simple – you set it up and it always sounds inspiring"), though Bono has apparently been getting some gutsy noises from Edge's tiny Boogie combo. Additions to Edge's treatments rack include a Yamaha Rev 7 ("more useful through a studio desk, it's a little too noisy to work with guitars") and the SPX90 ("I use that a lot, a great little device"). Korg SDE3000 delay lines still inspire him ("but the modulation control only has 5% of useful travel, the other 95% is rubbish").

Edge's keyboard work has been progressing since "Unforgettable Fire". In the making of the current album he's played about half the keyboards so far used – at this early stage in the studio Edge tends to start things off with guitar, and if Eno's there he'll play keyboards more or less live. But Edge is getting more and more interested in his DX7, although "I'm not a keyboard player," he told us, "but I play keyboard. And of all the keyboards I've tried and had time to work with, the DX7 is the one I'm finding the most stimulating. It's certainly not the sort of keyboard you can immediately sit down at and start programming: I still tend to edit sounds that already exist, than starting from scratch."

The group had to decide how to incorporate keyboards into the live set when they took the "Unforgettable Fire" songs on the road – either they had to bring in a keyboard player, or program sequencers to do the job. "Originally," Edge said, "I thought we needed a keyboard player because I just didn't like the idea of machines doing things. But then we decided that there's too much chemistry involved in the band to bring somebody else on stage, except for a possible guest spot. To preserve our 'big sound' we knew that we had to have keyboards in there so I started looking at different sequencers and ways of working. I finally decided to use sequencers (an Oberheim DSX) in the most simple kind of way. For most of the songs that meant as far as it was practical working out a four-bar section of the song and having the sequencer in for the whole song, switching it out where it wasn't required, really basic. So rather than it being something a musician would play it becomes just a sort of background to the real musicians on-stage. I'm sure we'll have to go through the same decisions for this next tour because the album we're working on at the moment has quite a few keyboards on it as well. A lot of guitars, too! It's going to be difficult to work out how to get these keyboards into the live set without ruining something unique; and I don't think we could ever work with your average session musician, it wouldn't work for us."

Latest acquisition in the guitar department is a lovely old '57 Strat, something of a departure as Edge has generally considered vintage guitars not worth the inflated prices usually asked (this one "wasn't expensive, less than £1,000"). What convinced him?

"I really liked playing it – and that's how I decide, does it inspire me? This one does. So I'm using that a lot, and I'm using my black 70s Strat. I don't really use the Explorer any more. I've got this new Yamaha jazz guitar (AE2000), single cutaway, fantastic, it's like a big jazz Gibson-style guitar, doesn't have any intonation control yet plays perfectly in tune, flatwood strings, and single or double coil pickup switches which really work. It gives me a whole new area of sound on guitar – the flatwood strings are totally different. And I've used the 'infinite sustain guitar' that Michael Brook's developed. It's electronic – but I can't tell you any more because the patents are pending. It has a similar effect to the E-Bow, but the disadvantage of the E-Bow is that it's either on or off, whereas this gives you all the mid points between no sustain and infinite sustain, and different levels of 'emergence' of the note."

Michael Brook, a musician signed to EG whom Edge met through Eno, is not only the inventor of this 'infinite sustain guitar', he also collaborated with the Edge on the soundtrack of Don Boyd's new film "Captive", which is about a kidnapped heiress. The Edge had always wanted to do a film soundtrack – he felt that U2's ability to convey mood was something that would lend itself ideally to soundtrack work. So he took advantage of a few months' break from U2 last summer to demo a few tracks, fix the collaboration with Brook – and then went in search of a film. After much initial hassle – he discovered, for example, that Martin Scorsese is not the easiest person in the world to get in touch with – Edge eventually contacted producer Don Boyd.

He also discovered that the movie industry relies on successful collaborations within the (big) organisation of a film. Edge is used to much smaller creative groups of people, say four musicians, a producer and an engineer – and was thereby used to much more direct control over what he produces. In film, however, he says, "Everything you do has a sort of backlash from four or five departments." The practicalities of putting film music together also proved educative – often it's down to trial and error, he found, and you can be lucky in making the required sections fit together. Edge also discovered he didn't like working alone in the studio – hence the collaboration with Michael Brook. The creative ear of someone else is so useful and important. Edge and Brook played virtually all the instruments for the soundtrack (Edge wrote primarily on DX7, fast becoming his favourite keyboard for its sheer versatility, and on a Washburn Festival electric-acoustic through a Rockman), though U2 drummer Larry played on one track, vocalist Sinead O'Connor on another. The LP version, which comes out on Virgin, has reworked and extended versions of the film tracks, plus some additional material.

We asked if Edge had to ask permission to do this project from Island Records, the company to which U2 are signed. He did, he said, but generally they're very understanding – they have a good relationship. We wondered if U2 have become more independent as a group as they've become more successful – does your own strength in fact enhance your independence?

"Well it does, for sure," Edge replied. "A band starts off with a deal that includes a yearly option to be dropped. Generally a group first signing up is in a precarious position for at least the first couple of albums — in our case we were in that position, but we also from the beginning had decided to try to control almost everything ourselves. And we had a manager who reassured the record company that it would be done properly.

"The weakest thing about a new group is their inability to run their own careers, be it management, administration, accounts and all that, that's just not where most musicians' heads are at. If it wasn't for our manager it wouldn't have been where we were at either, the last thing that was on our minds was all that sort of stuff — apart from artwork and the creative side of things. As we've gone on we've seen how crucially intertwined the music and the business are.

"I think record companies and managers generally have a very poor reputation in the business. Some of it is justified, but some of it is artists just not taking responsibility for their own destiny. They put themselves in the hands of managers and record companies, then wake up one day and find their career is no longer in their control, or things have happened that they don't agree with — and wonder why. It's not an easy situation to rectify, because obviously writing and recording material, and touring, is so demanding that to get into the strategy and business side of it is virtually impossible. But it's something you've got to do if you're very conscientious about where you're going — you've got to have your finger on the pulse on that side of things as well as on the music side."

Edge said that the best advice he could give about the business side to emerging bands is the word 'clarity'. Don't ignore problems in the hope that they'll go away, he told us, and if and when you get signed to a record company, make sure you keep going there and build relationships with the people concerned. Like a band works on relationships, the same is true within a record company. U2 did that from the beginning, and made a point of finding the time to do it — not always easy in the hectic first years of a band's career.

"Look for advice from the people around who are qualified," Edge continued. "We did that from the start — for example, in terms of getting the right management. That was something we discussed with several people in the business in Ireland — and eventually found someone we thought we could really trust and who would get on with it and whom we thought was capable. And then things like venues to play, we'd find out what the place to play in a certain place was, we'd consult our agent, and other bands, other managers. Anything we didn't know about we would find out about from people around — there are always people whether you're living in Glasgow or Birmingham or Manchester or London. It's down to putting yourself out, making a few calls, getting to know people who might be able to help. Advice generally — unless you're talking about lawyers — is free. Take a lot of it, I would say, take a lot and use your head.

"And... we used to hassle people, you know? We used to ring people late at night, annoy them, that sort of stuff, so there's a certain amount of neck involved. But generally people had time for us 'cos they could see that these guys weren't wasters, they've got something worth spending a couple of minutes talking to them about. If you've got that, if you've got some good material, you're playing gigs, you're pretty good, I think people will put themselves out for you. I know I have — just bands that you see around town, you get involved, see if you can help them out at all."

And so the time comes to leave the Edge to his slow but steady progress with the new U2 album. A last thought on technology and music, perhaps? "People have got freaked out about options, and flexibility," Edge reckoned. "I don't think anything good or useful has come out of that mentality. All the great rock 'n' roll guys came out of just throwing together a few crazy boxes and working with that — Chuck Berry, Bo Diddley, they didn't have fancy amps. They used one sound for their entire career. The sound is secondary; it's what's done within that sound that's interesting." Amen.