Ambient Drum and Bass, Artcore, Intelligent Drum and Bass
4 - Major
Drum and Bass
Ambient, Breakbeat Hardcore, New Age
Ambient Jungle
Jazzstep, Liquid Drum and Bass, Minimal Drum and Bass
The early 90s is probably the most chaotic period for musical development in the history of EDM, and while there were many new musical spheres that splintered out of rave at the time perhaps none are murkier in origin than drum and bass. The common wisdom is that first there was breakbeat hardcore, and then there was darkcore, which morphed into jungle, and then that turned into drum and bass. It's true that breakbeat hardcore is the common ancestor, but it's hard to say the rest of the line proceeds as stated because these genres developed almost simultaneously. Here's a more accurate timeline: breakbeat hardcore comes about around 1990, splintering out of the britcore hip hop scene, but doesn't solidify stylistically until around 91. Then, in 92, darkside and jungle develop in parallel as producers start moving towards a darker, more aggressive sound while the mainstream side of breakbeat hardcore becomes increasingly silly and childish. Then, in 93, atmospheric drum and bass (specifically, an early form called ambient jungle) begins to pick up steam - the only caveat being that LTJ Bukem has actually been making it since 1991 and it's impossible to really separate the jungle influences from the breakbeat hardcore ones. Oh, and that's not even getting started on whether jungle is a form of drum and bass or not, an issue that will probably remain hotly debated until the end of time
Anyways, it's a lot to understand why atmo dnb exists than when or how. Jungle was itself a reaction to toytown techno and other forms of hypersaccharine breakbeat hardcore, so atmospheric drum and bass acted as its own reaction to the dark sounds of jungle and darkside. Instead of creating edgy, aggressive music just for the dancefloor, atmospheric drum and bass drew from the calming sounds of ambient and new age, yielding a style that was not only more peaceful, but also more suited for home listening. Much like the similarly newborn IDM, atmo dnb was marketed a lot by labels as a more artful form of jungle, one that used breaks as part of a wider tapestry of deep, meditative music. Of course, just as with early IDM, the music itself wasn't particularly far removed musically from the dancefloor music it spawned from, and while IDM found its home in the leftfield and experimental side of electronic, atmospheric drum and bass very much remained dance music.
The earliest forms of atmo dnb were heavily rooted in the same primordial sounds of breakbeat hardcore and jungle, but over time producers started to move away from the chunky grooves and minimalist sound palettes, yielding some of the first distinct drum and bass music. Atmospheric drum and bass remained a prominent force throughout the rest of the 90s as a more complex alternative to the straightfoward sounds of hardstep and jump-up, even spawning another early subgenre in the form of jazzstep, but by the time the 2000s rolled around the oldschool approach of atmo dnb was starting to become old hat. The baton was picked up in the new millennium by liquid drum and bass, a more modern interpretation of the style that retained the airy, ethereal sounds of atmo dnb but interpreted it in a much slicker, more synthetic style that better fits the contemporary drum and bass landscape. Atmospheric drum and bass isn't totally gone, though, not by a long shot - like jungle, it retains a significant cult following, and has even seen a revival in hobbyist music circles lately due to the rise of a new breed of atmo dnb artists like Sewerslvt that draw influence from depressive breakcore and exaggerate the atmo dnb sound, contrasting full-on ambient sections with hard compressed breaks and bass.
Link - "Amazing Amenity (Chameleon Remix)" from Artcore (1995).
Goldie - "Timeless" from Timeless (1995).
BT - "Memories in a Sea of Forgetfulness" from ESCM (1997).
Alaska - "Kodiak" from The Mesozoic Era (2010).
Sewerslvt - "Mr. Kill Myself" from Draining Love Story (2020).