To experience Autechre live is a rare and intense treat. It is at once mentally, physically and aurally taxing. The bass is bowel-loosening. The kick drums pound your chest so hard you fear it might bruise. And the rhythms are so complex your brain often can’t compute them quickly enough before they evolve or fragment.

It’s just after 11pm on a Saturday night and the long line at The Hi-Fi is full of people ready for such an experience. Testament to Autechre’s consistency in releasing exciting music over the span of their 23-year career, the crowd tonight is made up of people of all ages – from those who were around for their earliest releases, to those just discovering this seminal act via their latest release Oversteps. As we make our way down the stairs we hear the door-staff yell out, ‘three tickets left,’ and the show sells out moments later.

The space is full but not overflowing and everybody seems to be holding a coat in one hand and a drink in the other, owing to the lack of a cloakroom. On stage, Rob Hall is delivering bass-heavy techno and scattered beats and is a great choice of support for Autechre. As Hall finishes his set, the lights in the room are turned off and a gigantic bass drone fills the room.

Apart from the green glowing exit signs and the fluorescent-lit ads above the bar, The Hi-Fi is shrouded in darkness. Even the lights in the fridges are turned off, with bartenders having to squint to find the beverage you ask for. On stage the only light comes from two red monitor lights, looking like sinister mechanical eyes and fitting in with the mood Autechre seem to want to incubate. The solitary sign of the group is the faint glow of equipment and the outline of two men visible from that small amount of illumination.

A cheer erupts from the crowd as Autechre start their hour-and-a-half assault on the senses with a succession of brutal, hammering kick drums. Wildly varied sounds come in and out of the mix, sometimes spacey and futuristic, sometimes industrial and often glitchy. Very rarely we hear a little of the lushness that can be found in some of the group’s more ambient-leaning releases. The only constant in the set is the presence of hard, displaced kick drums and extremely heavy bass.

Looking around, there are heads nodding and feet moving but very few people actually attempt to dance during Autechre’s set. As they play, the brain is in a constant attempt to latch onto recognizable or repeating patterns in the drums, but the patterns are so frequently changing and in such difficult time signatures that the task seems impossible for large amounts of the performance. By taking away many of the elements people find easy and comforting to grasp in a club setting – 4/4 drum patterns, simple rhythms, visually engaging lighting – Autechre force the audience to continuously re-evaluate what they are hearing. The mind, as with the sound emanating from the speakers, is in an endless state of flux. It is challenging, yet mesmerizing music.

Towards the end, they move into some relentless 4/4 techno before returning to the more schizophrenic beats the rest of the set has been dominated by. As they finish, the two men wait and accept our applause before taking their laptops and walking off stage, still hidden by darkness. The crowd files out into the city night, buzzing and in awe of the performance they have just witnessed. It was hard, it was loud, it was difficult. And it was amazing.