Roni Size Plays World Record Rave 1,375 feet Beneath a Welsh Mountain

RONI SIZE PLAYS WORLD RECORD RAVE 1,375 FEET BENEATH A WELSH MOUNTAIN

After a two-hour Go Below-led descent through waterlogged passages, ravines, zip lines and abseils, a small group reached Deep Sleep in Cwmorthin slate mine for a one-off world-record rave.

On 15 October, Roni Size performed a one-off G-SHOCK Sessions set 1,375 feet beneath Eryri, North Wales.

Vibration transducers drove the music into the slate while geophones and hydrophones captured what travelled through rock, water and mud.

Before the set, Hen Wlad Fy Nhadau filled the underground chamber, continuing a Go Below tradition of playing the Welsh national anthem inside the mine.

Evidence from the strictly ticketed event is being submitted for independent verification as a world-record submission.

LONDON, 16 October 2026: Going to this rave wasn’t for the fainthearted. To get to see it, ballot-winners needed to earn the dancefloor. So yesterday, a small group in helmets and harnesses descended through Cwmorthin slate mine for around two hours, crossing waterlogged passages and underground ravines before taking on scrambles, zip lines and abseils to reach Deep Sleep - 1,375 feet beneath the mountains of Eryri.

At the bottom, supported by G-SHOCK radio’s DJ Nav, Roni Size played a one-off set inside a vast underground chamber reached with support from Go Below's qualified Mine Leaders. G-SHOCK staged the event as a reward for the people with the deepest commitment to toughness and music as it launched its new Mudman.


A DANCEFLOOR AT THE END OF A TWO-HOUR DESCENT
There was no walk-up queue and no shortcuts. Lucky (or unlucky) ballot winners put on their helmets and descended on a gruelling two hour descent into the deepest reachable place in the UK to get to the set. The inward route followed miners' stairways, cold and flooded passages, loose slate and vertical drops, abseils, ziplines and scrambles. The rave only appeared after the final descent, with the decks, sound, lighting and recording equipment carried in on people’s backs.

THE MOUNTAIN BECAME PART OF THE SIGNAL CHAIN
Before the event, the sound team measured the mine's impulse response using convolution reverb. During Size's set, vibration transducers sent elements of the music directly into the surrounding slate. Geophones and hydrophones then captured what travelled through the rock, water and mud, bringing Cwmorthin's acoustic and geological response back into the performance.

The result was a set shaped by the mountain and the mine itself, rather than simply played inside it - drum and bass moving through a signal chain made from stone, water, engineering and the crowd. The finished performance was prepared for G-SHOCK Radio, with the full set soon available on Mixcloud.

Full Roni Size set on G-SHOCK Radio Mixcloud: https://www.mixcloud.com/GShockRadio/


RONI SIZE ON TAKING THE SOUND BACK UNDERGROUND
Ahead of the descent, Size connected Cwmorthin to the Bristol sound-system culture that shaped his career:  "Back in Bristol, we'd put on a party wherever we could, and some of the sounds came from what we called happy accidents - playing a track at the wrong speed, hearing something that sounds new but still works. Raves could take place in some crazy and unexpected places, on someone's front lawn, down in tunnels, but what I've always done is play to the environment and the crowd. The set is a living, breathing thing that reflects the people there with you."

"By the time we're 1,375 feet underground, everyone there will already have shared an adventure. And how much more could you reflect the environment than by pumping a set into the mountain, hearing the sound travelling through the slate, rock and mud, and bringing it back into the mix? It's the most underground of underground raves ever."



A DIFFERENT CHAPTER IN CWMORTHIN'S SOUND HISTORY
Cwmorthin has carried sound for more than two centuries. Quarrying began in 1810, and the mine's original soundtrack came from drilling, tools, wagons, running water and voices travelling through slate. Beyond the workings, Welsh quarry communities were centres of culture as well as industry, with bands, singing, poetry and eisteddfodau woven into life around the mines.

Go Below has continued to use sound as a way into that history, including underground carol services and performances of the national anthem on guided trips. Roni Size's set brought a different frequency into the chamber, but the connection between music, community and place was already there.

Before Roni Size took over the decks, the team played Hen Wlad Fy Nhadau through the underground sound system. The Welsh national anthem filled the Deep Sleep chamber as the group gathered beneath the mountain, locating the rave unmistakably in Wales before the first breakbeat landed.

It was not the first time the anthem had sounded underground at Cwmorthin. Go Below's team has played it inside the mine on multiple previous occasions, turning a planned transition between sets into an underground tradition that honoured the heritage of the mine.

THE FIRST MUDMAN DROP
The event also gave the group the first chance to get hands on with the new £200 GDG-B100 MUDMAN ahead of its wider release. Built for harsh environments, the watch is shock, dust and mud resistant, water resistant to 20 bar, and features a high-contrast MIP LCD, red LED backlight and Smartphone Link.