"A lot of people talk about progression but at the same time, when things change, they don't like it,"  laughs Quest. "You can't have it both ways! But at the same time, it's about not losing touch with what you were about in the first place."

So then, how best to move forward without sacrificing your essence? Dubstep is an entity in constant flux, so it's a question Tempa's scene-defining Dubstep Allstars series has been forced to ask again and again over the past 8 years. The genre has traveled a long way from its origins in Croydon bedrooms and bassbins, and the acres of space that its early innovators left within its skeleton have fleshed out, creating a veritable monster's ball of new hybrids - some stunning, some markedly less so. So as the series reaches its ninth volume, with the genre reaching new heights of popularity and making equal headway into charts, clubs and headphones worldwide, it's a question that feels more pertinent than ever.

On Dubstep Allstars Vol. 9, Antisocial Entertainment members Silkie and Quest answer by keeping the mix grounded within their own musical history. The path they've traveled over the last few years has run parallel to many of their contemporaries. Its roots are the same, and it has continued to intersect with other forms of the genre over the years. But where many producers' sounds have changed almost unrecognisably across the course of their careers, both Silkie and Quest have kept a broadly similar mindset throughout. It's as if they reached its evolutionary pinnacle early on - absorbing the warm tones of house and garage, stirring jazz, electro, grime, funk and R&B into the equation - and since then have honed it and subtly twisted it into different forms. Acknowledging that, their selection for Dubstep Allstars Vol. 9 doesn't simply pack the mix with new dubs. Instead they've chosen tracks from across the whole of their releasing career.

"In the last two years a lot of people have come to the sound that haven't heard dubstep before," explains Quest, "so we're thinking about people that might just be hearing us for the first time. It's an introduction, and we're taking you where we're going as well."

Theirs is a many-limbed, many-hued vision of the genre, but its roots still lie firmly embedded in London soil. Like so many of their contemporaries, that's largely down to something they both cite as a major influence: the sensuous swing and bumpy dynamics of UK garage, which was dominating the airwaves when they were growing up. "My dad was the first person who introduced me to garage," grins Quest. "I remember he gave me a tape of EZ and it just blew me away."

Coming from a very musical family, Quest had been playing the bass guitar from a young age, but had always been drawn to the idea of DJing. He pressed his parents to buy him a pair of 1210s and taught himself to mix, before making the jump to production and joining a grime crew. Experience playing a real instrument, he says, was a crucial ingredient stirred into the melting pot of his sound. "It taught me the ethic of real music. You look at structure a bit more, stuff like that. I draw from everything, and it made me want to incorporate all these things from my past into what I make now."

Silkie, by way of contrast, had no musical training, yet somehow alighted upon a similarly multidisciplinary approach to production, writing tracks where jazz, funk and soul could weave quite comfortably in the mix around booming sub-bass and springy electro riffs. Like Quest, his interest in a wide variety of genres led him to start crumbling the boundaries between them. "The musicality in my tracks came from a desire to emulate the music I loved - garage and 90s R&B," Silkie explains. "It forced me to learn to incorporate that sound into my music. I feel a compulsion to add the jazz and the soul to the music, and find it harder to leave it out."

As both separately became more invested in making music, it was inevitable that sooner or later the two would meet. In the end, that opportunity came through future Antisocial member and mutual friend Heny G. "He said, 'My mate Silkie, he makes beats just like you!'," remembers Quest. "He introduced us and the moment we met, we just hit it off." Silkie asked Quest to join Antisocial Entertainment, a group set up by himself and Harry Craze as a producer-led alternative to grime's usual MC-led crews, and, in Quest's words, "the rest is history."

Silkie had already been producing dubstep for some time when Quest stumbled into it almost by accident, after Skream started playing his track 'Hard Food'. "I was just dipping my foot into the water with dubstep," he laughs. "At the time I thought 'Hard Food' was a reggae-grime track, but Skream got hold of it, and I remember I got a message from him at about 2 in the morning wiling out, going 'This is sick!'"

With 'Hard Food's dubbed-out vibrations rippling around the resonance chamber of FWD>> at Plastic People, the pair went on to release a series of records through labels like Mala's Deep Medi and Skream's Disfigured Dubz, establishing them as distinctive voices within the scene. The lustrous piano chords of Quest's humid roller 'Deep Inside', released in 2008, felt like an inversion of Silkie's brittle 'Cyber Dub', which transferred sub-bass dread hard into the digital domain. Later, Quest's jazzy-as-hell 'The Unknown', all soprano sax trills and spring-loaded drums, proved a neat counterpart to Silkie's debut album City Limits Vol. 1 and the buoyant clarinets of 'Concrete Jungle'.

It's these tracks that form the backbone of Dubstep Allstars Vol. 9, creating a bridge for listeners from their past music to the present. It was with that idea in mind, Quest explains, that they decided not to simply record a mix packed with exclusive dubs. "This is a landmark for us," he shrugs. "Why shouldn't we include our older tracks? We wanted to show people: This is why we're Antisocial. This is why we're Quest and Silkie."

So it's telling that Dubstep Allstars Vol. 9 doesn't follow any particular narrative as such. Instead it bounds from one energy level to another with all the fitful enthusiasm of a sweaty club set, where any pauses to consider are repeatedly swept away by the compulsion to start moving again. It's an approach which suits their selection. Just as with many past instalments in the series, the duo draw the mix's tracks from a small pool of close-knit producers. Chief among them is Swindle, who has recently been collaborating with Silkie on fluorescent grime instrumentals for Elijah & Skilliam's Butterz label. It's Swindle's 'Superhero' that opens the CD, plunging live cables into the midrange and electrifying the mix to life. Another crucial inclusion is 'Eyez VIP' by Digital Mystikz's Mala, whose label has released many of tracks included on the mix - its wind-burned synths ramp the dread up to staggering intensity.

It's these touches that define Silkie and Quest's mix and keeping it rooted in the history of the sound. Keeping true, in Quest's words, to "the ethic of what we've always done". But it intends to use that as a base from which to push forward. The Antisocial Entertainment crew provides a space within which to bounce ideas off one another, something that fosters the duo's own development as well as that of upcoming producers. "He's never been taught music, he's just talented at it," says Quest of Swindle, one of Rinse FM's latest recruits. "That taught me things as well - we're all learning off one another." That sort of feedback loop, he explains, is what helps keep their approach vital. "Antisocial branch out to everything. That's one thing we've all got in common, rather than just going with one sound and battering the life out of it."