Mick Harris has many names: Scorn, Lull, The Weakener, Quoit, Monrella and, he reveals, Mickey Mongoose. "I'm a hyperactive little bastard," he grins. "And you haven't got to live with me! The wife can tell you the rest!"

His energy levels might explain his dizzying contributions to music. As the drummer of Napalm Death in the late '80s, he invented the blast beat and the term "grindcore." Put off by "that whole sex, drugs, rock & roll thing," he left the band in the early '90s to explore electronic music. Under the name Scorn—first with ex-Napalm Death member Nic Bullen, but soon solo—he explored a dread-filled downtempo sound that, 25 years later, seems visionary. Other aliases refracted ambient, techno and drum & bass through his gloomy lens. And that's to say nothing of his role in the Birmingham scene. Surgeon made his 1994 debut EP in Harris's converted toilet studio, and it was Harris who connected him with Regis, helping kickstart Downwards Records and the Birmingham techno sound.

Harris has a cult following, and the wider music world pays attention every now and then. A decade ago there was talk of Scorn's uncanny foreshadowing of dubstep; last year, a 1994 Fret record got a new lease of life on Objekt's Kern mix. But lasting success has eluded him, and his energetic personality has, he says, led him to "burn bridges" over the years. In late 2011 he retired his Scorn alias, got a job as a technician in a local music media college, and stopped making music—for good, it seemed.

But this year he returned. I met Harris at Berlin's Atonal festival, where he was debuting a new live show as Fret, which he'll follow with an album on Karlrecords in October. He'd just finished an ear-piercing soundcheck when he joined me on a sunny park bench outside the venue. He seemed ecstatic to be back on the road with his wife, Helen, and proved a frank and enthusiastic interviewee, waxing lyrical about dub, dropping anecdotes about the young Karl and Tony, and revealing his habit of cooking up extravagant burgers. As he put it, "They can get silly, but why not?"

Why did you take a break from music a few years ago, and why did you come back?

A break was something I personally needed, and I really thought that I wasn't going to come back with anything, let alone an album. The demons, the self-doubt... lack of confidence, you know. It was just that constant battle. I really did think, I'm just doubting everything, I'm hating everything, I'm not enjoying where life's going. Bills just weren't getting met.

Music was your full-time job?

Yeah music had been my full-time job, and I was lucky, you know, with all the travelling I had done, the people I've met, the opportunities I've had. I've burnt a lot of bridges through those years—frustration more than anything. I have to be honest and hold my hands up, I know where I've been bang out of order with just running my mouth. Which I've managed to get a hold of. I've relaxed as a person, I think. The last few years I've managed to control it, rather than just let it fire, and then sulk, and feel ashamed and upset afterwards.

Luckily, having some friends at the local music media college in Digbeth, an opportunity came up. They took me on part-time to start with. And I loved that. They could see the energy, they were like, "Wow, we've got a technician that actually enjoys what he's doing." Some of the students know me from my past—certainly Napalm Death. That's always fun. And I've been able to give them a few little pointers, I think, from all the mistakes I've made. Look at Tony [Surgeon], you know. I'd already made mistakes when I met Tony in the mid-'90s, and I told him, "Don't do this, don't sign that, because I've made a real mess, Tony, and I can't go back on that." And he still to this day respects that. I've made some big mistakes. Just clouded judgement.

Decisions to do with signing contracts?

Terrible! Terrible. I own no rights to anything. Out of all the projects—and you know there's a lot of projects, a big discography—Earache is the only label that still pays me a royalty. I took a buyout when I left Napalm Death because I really didn't know where it was going. I had a son on the way so I thought it was a wise thing to take a lump sum. The solicitor wasn't too pleased with that. Basically every project I signed the rights away. I didn't even look at what I signed. A thousand pounds here, two thousand there. All I was thinking about was keeping the ship afloat. Absolutely nothing else.

So having a little break helped give you perspective.

Without a doubt. Getting the job let me realise what I had and what I'd thrown away, what could have been. You've just got that little time to think about situations.

And you weren't making music during this time?

I'd have a little tinker, but five or ten minutes and the self-doubt—it was still there, the self-hatred was huge. I wouldn't even save [the project file]. Every time thinking, It just sounds like Mick Harris. What's the point? Just forget about it.

So let's go forward to November of last year. I wrote to Thomas from Karlrecords asking, could I get some copies of a Painkiller [Harris's group with John Zorn and Bill Laswell] record that he'd reissued? He said, "I'll send you four, no problems. Appreciate you writing, Mick. Do you have anything unreleased in the archive?" I said, "Nope, no chance."

Over Christmas me and Helen had a good talk—mainly Helen wanting to address the situation. "Look Mick, you're not doing anything. I'd really like to get that spare room back. You're either going to do this, or you're not. I think you can do it, you're just holding yourself back, time and time again. Forget the self-doubt, you've got your style, it's not a problem. Grab it, embrace it." So I thought, Maybe, maybe. And after Christmas, one day, I'd been up there [in the studio] five, six, seven hours. And she didn't interrupt. [She didn't even] shout, "Mick, your turn to cook tonight"—we have a rota. And that was it, that was the spark.

Why the Fret name?

I thought what I'd started was sort of Fret-sounding. I'd made one Fret record [in the '90s], it happened really quick, it came out, it disappeared. No disrespect to Karl [O'Connor]—it was on his subsidiary label Resonance—but he advised me not to put my name on it. With the lack of confidence, that's classic Mick Harris! Like, "Yeah, maybe I shouldn't. I do my Scorn thing, that downtempo dub thing. This could go against it."

Talk about how you met Tony and Karl. They're a bit younger, right?

Leaving Napalm, I'd heard about techno—I was a big Meat Beat Manifesto, big Wax Trax! fan. I was told about this one record shop where I could get some techno, called Way Ahead Records, where Karl was working, and I went in. I think I was asking for a few obscure experimental things. He said, "You might like this, we've got an album coming out next week by a guy called Jeff Mills, Waveform Transmission Vol. 1. I said, "Nah, I've not heard of him." He said, "I think you might like him. Come in next Tuesday, that's our delivery day."

And that's where it all fucking started, didn't it! I remember going that Tuesday. I was first there, of course. Box had just come in. I think he'd got three copies for the shop. He put it on and it was just that instant, "Wow, that's something new, listen to that!" And he said, "Well every Tuesday we have a lot of new stuff in, I can start putting stuff aside for you." It just spiralled from there. I got obsessed with it! Tony said something recently in an interview: "Mickey had a bigger techno collection than any of them!" I loved it! I wasn't a DJ, I was a listener. It was the sound, the dynamic.

I think I invited Karl round my flat, and we just became really good friends. Karl had grown up with a lot of synth music, where I'd come from punk, but we were sort of crossing over, me going that way, and him enjoying the punk element of things, and the darkness and whatnot.

Were you teaching him things in the studio?

Yes, he'd come to my studio. I was self-taught, terrible engineer. I learnt from going to the BBC and going to professional studios with Napalm. I remember watching Bill Laswell and seeing red lights and going, "Wow, you shouldn't do that, should you?" Bill—and he's not a man of many words, he's a fucking deep thinker—Bill just looked at me and shrugged. And I thought, If Bill can do it, it's got to be OK. So that was a real lesson for me. So I bought my first sampler, a little reverb box and a four-track, and I used to do the Napalm Death intros. Sort of horror soundtrack-y stuff, but it was a start. The kit went to an eight-track, more rack gear, bigger mixing board.

Me and Karl had been to see Aphex Twin in '93 in London, and I said, "I want to do some more electronic stuff." Karl said, "I'll tell you what, Mick, my mate's got an 808 and I've got my [Sequential Circuits] Pro 1. Let me bring those around." I've still got that track that we made, and it doesn't sound that old, I'll be quite honest. So we just hit it off really well. He'd come round as much as he could. Then he announced he was going to start the Downwards label, and I'd come across Tony in '93, when I started to go to the House Of God club.

How did you get into going to House Of God?

One day on my mountain bike, I saw this flyer: "Twisted acid techno." And it just drew me—I'd never seen a flyer like that. I thought, Oh, sounds ace! Plus, they've got a dub room! How could I go wrong? So I told two of my friends—we were all mountain bikers. We used to do space cakes before going in. By the time we'd ridden down there it'd all come on, we'd lock up our bikes and we'd be there 'til 3. I'm not a dancer, a sideliner. I want to listen and take it in. And instantly, I was attracted to DJ Surgeon. It was the sort of techno I wanted to hear. He was playing the Mills, he was playing the Hood, the good stuff like Dave Clarke, DBX.

I used to go down [to Tony's house] to score weed. They were all DJs there, all ex-students, including Tony himself. Tony was the laziest, he wouldn't be out of bed at four in the afternoon. One of those. And I always wanted to talk to him. One day I said, "Does Tony ever come out of his room?" "Just knock him up, lazy bastard!" And he was just getting himself together, and I said, "Sorry—I really like your DJ sets, really like the music you play, Tony." That was about it.

A few weeks later, he mentions he's borrowing a drum machine off somebody, he'd got a synthesizer, a classic Poly-800. Me being me, I said, "Come round my studio, you can use it. As long as you bring Helen a cake—that's my girlfriend." I thought, He isn't gonna come early. He said, "About 3 o'clock?" So he came round with the cake, and I quickly showed him—he'd done an audio engineering course and that—and I just left him in there.

The studio was in your toilet, right?

It was! I had a guy come round and cap the toilet, £10. £300 to have it damp-proofed, and it was a perfect little room. And I think Tony made three tracks over two days—he came back the following day with another cake. And they were amazing, we'd listen to them in the lounge. I said, "My friend's starting a label. I'm gonna tell him about this." And Karl came over and they just got talking. And Karl said, "Well, you do one more track, and I'm gonna put that out." And well...

The rest is history. You were saying you weren't really a dancer—were you ever tempted to get deeper into dance music culture?

I wanted to have a go at DJing. Bought a pair of MK2 Technics, Karl picked me up to buy them. They weren't set up right so I thought, I'm gonna ask Tony to come round. And it was just something that Tony said, it just threw me. He asked, "What do you want turntables for!?" Classic Mick: no confidence. I couldn't tell someone that I looked up to, "I want to have a go at DJing." I couldn't say that to Tony. Felt really bad. As soon as Tony went, I got upset. "Nah fuck that," I said, "I'm selling them." Called up Karl: "Do you want to buy my turntables?" "You've only just bought them this afternoon!" "It isn't for me, Karl. Knock £50 off them? You've got the receipt."

Dub studio techniques are central to your music. When did you first encounter dub?

John Peel. I used to hang out with my cousin up until '79, when he told me he was off to university. He was the clever one of the family, and he told me I should start listening to John Peel. "He runs this radio show, Mick. Check him out." And that was the best bit of advice ever. Peel was the music teacher for me. I couldn't wait to get home from school to edit the tapes. I'd never bothered with reggae—never been exposed to it. And Peel played this B-side, played this instrumental—I do believe it was a King Tubby. "Wow, listen to that! It's sparse, listen to all that echo, and it's all overloading... oh, that sounds killer!" So I just delved, as you do. Discovering who's doing what, you know. Discovered King Jammy, Scientist and Scratch Perry.

It wasn't easy to get Scratch Perry and King Tubby stuff. We had a local reggae shop in Digbeth called Don Christie's and it was moody. You sort of stayed away. Lot of ganja being smoked in there. And I just wanted some of these fucking dub 7-inches. A few times I attempted it: get off the bus, anticipation, thinking, Am I gonna do it? And then looking at the door, and the heavy smoke in there... Not today. In later years, I guess '94, '95, the basement became the drum & bass and jungle vendor. But it had changed from those early '80s. The rastas—they were chilling, weren't they? But it just looked imposing.

I wanted to ask about fishing. Quite a few of your titles reference it. For instance, Lifford Reservoir, mentioned on the new album, is a fishing spot, isn't it? How long have you been doing it for?

I've fished since I was a kid. Took a break in Napalm—I felt that it wasn't the right thing to do in Napalm. There's just something about it. Then I heavily got back into it when I realised that was a space that was really good for me. Just to get away from it all. It's not about the fish for me. It's getting out of Birmingham. That's my release, going to the river.

So it's something you've always done on your own?

Absolutely. I am a loner, I always have been. Never had friends as a kid, the kids around the road wouldn't let me play with them. They were nasty bastards, as kids can be. All a learning experience. It knocked my confidence, but it made me that loner, I guess. Napalm—that was my first, if you want to call it, unit of people where I was involved. So it was hard having to get out of that, cause I'd done it for so long, they were my mates. I was always a loner, but my Mum liked it. Dad would always say, "Doesn't he ever go out?" And mum would say, "He's not in trouble with the police or anything, he's not out starting fires, robbing cars. Leave him! He goes up town on a Saturday." "Yeah, to buy more of that bloody noise!"