Roni Size is heading underground, and not in the usual club sense. The Bristol drum and bass pioneer will play a one off set 1,375 feet below the surface of an abandoned slate mine in Wales on October 15, in what organisers are billing as the Roni Size deepest rave ever staged. The event is a world record attempt, and the audience will be a limited group of ballot winners.
Where the Roni Size deepest rave will happen
The venue is Cwmorthin, a disused slate mine in Eryri, the national park formerly known as Snowdonia, in North Wales. Reports put the chamber at 1,375 feet down, with some outlets rounding that to roughly 1,400 feet. Getting there is part of the experience: guests descend through guided mountain approaches, miners’ stairways, flooded passages and ravines, with scrambling, zip lines and abseils down rock faces along the way.
The event is organised by watch brand G-SHOCK, part of Casio, as the launch of its new GDG-B100 MUDMAN model. Places are handed out through a public ballot on the G-SHOCK website, entries close on October 9, and winners must meet age, fitness and equipment requirements, according to T3. The brand says it will submit evidence from the night for independent recognition, so the record is a stated attempt, not a confirmed title.
Turning a mountain into part of the sound system
The technical idea is what separates this from a novelty gig. Vibration transducers will push parts of Size’s performance directly into the surrounding slate, while geophones and hydrophones capture how those frequencies travel through rock, mud and water. The team measured the mine’s acoustic response in advance and built that data into the set through convolution reverb, which T3 describes as making the mountain part of the signal chain. G-SHOCK calls the captured result Eryri’s “lithoacoustic signature.”
Size, speaking in a press release quoted by Mixmag, called it “the most underground of underground raves ever.”
Why it matters for dance music
Brand backed immersive stunts are now a regular part of the electronic calendar, and this one leans on genuine sound design rather than just a dramatic location. It also keeps a drum and bass figure of Size’s standing in the spotlight outside the festival circuit. For a look at how the UK scene is organising around grassroots venues, see our piece on the Sonny Fodera LIVE Trust pledge, and for the season ahead, The Warehouse Project 2027.
What happens next
The ballot closes on October 9 and the set takes place on October 15. It will be broadcast on G-SHOCK Radio via Starlink that day, and the full recording is due to be released later on Mixcloud. Anyone not lucky in the ballot can hear how the mountain sounds there.
FAQ
When is Roni Size’s underground rave?
It takes place on Thursday, October 15, 2026, in the Cwmorthin slate mine in Eryri, North Wales.
How deep is the mine?
The set is staged about 1,375 feet underground. Some outlets round this to nearly 1,400 feet.
How can you attend?
Places are allocated by ballot through G-SHOCK’s website. Entries close on October 9, and winners must meet fitness and equipment requirements.
Can you listen without going down?
Yes. The set is broadcast on G-SHOCK Radio via Starlink on October 15 and will be released afterwards on Mixcloud.
Bottom line
A drum and bass legend, a flooded Welsh mine and a mountain used as an instrument: the Roni Size deepest rave is a stunt with a real technical idea behind it, and the record claim will be judged after October 15.
