The last gig of a bit of a frantic period at the end of April into early May, before a couple of weeks off from gigging, this was a hastily arranged, last minute attendance. I had a ticket for the A&P show earlier in the week, but the announcement of this show allowed me to take up a friend's spare ticket at The Knife's brilliant show in Camden instead. Happily, it all worked out well, and I didn't miss anything.

It did surprise me a little that the attendance for this Sunday show wasn't as high as I might have expected, but by the time the headliner was on, it was certainly a good enough turnout.

First act was a new one on me. Machine Woman is one woman, sat in front of a table with a laptop and various controllers. And while the music – downtempo, very dark ambient, in the main – was good, it was not much of a "show" (as one-person-with-a-laptop gigs often end up), and I'll confess that I'd be much happier listening to her music in the comfort of my own home.

A rather more involving and punishing experience followed that. I'd heard of the name Necro Deathmort before the gig, but hadn't got 'round to listening to them. I was perhaps expecting something a little more "traditional" in extreme metal set-up, but instead was broadsided by a brutal noise assault from two men onstage armed with guitars and tons of electronics. This was certainly extreme, but more in the realms of Godflesh than anything faster. Oh yes, this was filthy depth charges of bass, squalling noise, and wrenching guitar riffs – the sound that might accompany the utter terror of looking into the abyss. The only complaint from me was that the set seemed to drag a bit in the end – half an hour of this intensity would have been more enough for me. Also: top band name (translates to Death Deathdeath).

I discovered Author & Punisher last year – as did many, I suspect – thanks to the filthy industrial doom of Terrorbird (and the impressive video that accompanied it), and in the end-of-year shakedown, the album Ursus Americanus made it into my top albums of 2012. And not to mention, it also allowed me to discover a number of other bands on the Seventh Rule label, whose bands appear to be making exactly the kind of extreme music I've been looking for for a while (my other great discovery from this stable being Batillus, who tread similar, but more metallic-based ground to A&P).

So I had been really looking forward to this show: and happily I wasn't let down. Quite a fuss has been made about Tristan Shone (for he is A&P) and his stage set-up, and it isn't hard to see why when you see it in the flesh. Rather than – like one of the supports and countless other solo acts – using just a laptop on stage, this highly-qualified engineer rather thought of the box and built his own rig, with various bespoke elements to control the sounds in interesting ways.

It allows for a more "live" show, for a start – and that live show is, like the support act preceding him, extremely harsh. Author & Punisher straddles the boundaries between drone metal and industrial noise, and somehow manages to make the two play nicely, with heavy industrial electronics only making the droning doom all the more intense and heavy. The sensory assault – this was a brutal forty-five minutes or so, one of those where it was impossible to know exactly how much time had elapsed, as the volume and heaviness made it difficult to think straight – also meant that the songs mainly bled one into the other, with little discernable gaps between the tracks, and it also appeared that there was a fair proportion of new material (from forthcoming album Women & Children) in the set.

But rearing out of the sonic murk, like monsters from the deep, were two of his best recorded moments. That first shock to the system most of us heard, Terrorbird, was despatched early on and was so heavy my skull was vibrating, never mind my teeth. Lonely was full of subterranean bass and sloooooow, heavy beats that felt like my head was being stomped on. And so it went – listening to his material at this volume was a revelation, and confirmed to me that I need a new and better stereo to be able to do this kind of music justice.

In the meantime, though, gigs like this will do nicely. Tristan Shone's technical prowess has certainly got him wider attention than his extreme music may otherwise have done, but we really should be concentrating on the music, as this is awesome, technical stuff that is pushing at boundaries that have previously barely been explored, and by the looks of things is taking a number of converts with him. Judging on his work so far, the route he takes next could be very interesting indeed.