Dream pop is a specific subgenre of Alternative Rock that emerged in the middle of The Eighties, and is commonly associated with the label 4AD Records. As befitting its name, dream pop lies in the middle between Ambient music and pop: it borrows the emphasis on ethereal soundscapes typical of the former and applies it to the catchy melodies of the latter. Theoretically this gives it the best of both worlds, since it avoids both ambient's excessive monotony or inscrutability and pop's shallower tendencies. In troper terms, it's basically the musical equivalent of Scenery Porn.
While the genre itself appeared in The Eighties, the Velvet Underground song "Sunday Morning" has been cited as basically the Ur Example of the genre, once again supporting the old joke that people who buy Velvet Underground albums will start their own bands.
Dream pop's indie status means that its bands don't have access to incredibly advanced equipment or funds in their quest for sonic beauty. Typical characteristics of the genre include heavily processed guitars and synthesizers, breathy, high-pitched generally female vocals - the occasional male vocals show up but they tend to be just as breathy - and heavy use of reverb and echo to give the songs a sort of celestial atmosphere. Basically, you can think of dream pop as the musical equivalent of Scenery Porn with a tendency to Perishing Alt Rock Voice. Thanks to its association with 4AD, the genre even had its own distinctive visual identity thanks to Vaughan Oliver and v23's work for that label: Minimalistic Cover Art designs employing very blurry imagery and occasional use of Deliberately Monochrome.
Generally, if someone says "dream pop", they're most likely thinking of bands in The Eighties on the 4AD label, such as Dead Can Dance, Cocteau Twins, Dif Juz and the genre's own Supergroup, This Mortal Coil. These bands represent dream pop's "classic sound" - all instruments and voices soaked in reverb, breathy vocals, introspective themes and creating a wall of sound out of generally sparse instrumentation, adding up to something that, all snarkery aside, is really quite beautiful. Most dream pop bands varied in terms of emotion between somber and depressing, terrifying and optimistic. Still, not every band on 4AD was dream pop (The Pixies, The Breeders, Colourbox and Throwing Muses were on the label) and not every dream pop band was on 4AD (Cranes, The Passions, Bel Canto, Galaxie 500 and The Dream Academy among many others were on other labels). While dream pop was intially a pretty unified genre, variations on the basic "ethereal soundscapes + pop melodies" formula soon appeared, in particular bands that focused more on guitars than synths. Pretty soon, the genre started splintering into a ton of other subgenres as well: Low went into Slowcore, Mazzy Star smashed together Dream Pop, Shoegazing and Psychedelic Rock, Love Spirals Downwards went into electronica, and so on.
Dream pop was an important influence on the emergence of Shoegazing, and starting with The Nineties the two genres began cross-breeding and eventually became indistinguishable. You're not likely to find many Dream Pop bands that use the "classic sound" of the Cocteaus or This Mortal Coil anymore, although there are a few new bands, such as Beach House, that continue the "traditional" dream pop sound. There aren't many of these, but they're pretty popular amongst indie kids. Instead, there's a ton of bands that are somewhere between dream pop and shoegazing (which in itself could be called Dream Pop taken Up to Eleven), most likely thrown under the umbrella term "post-rock" - a good example of this would be Sigur Rós.
- A.R. Kane
- Au Revoir Simone
- Azure Ray are dream pop, with the overwhelming reverb replaced by folk and indie influences.
- Beach House (unique combination of dream pop and Surf Rock)
- Bel Canto
- The Blue Nile (very strange combination of soft rock, easy listening, soul, and dream pop. If The Cocteau Twins grabbed a vocalist that sang like Morrissey, and stole all of Michael Bolton's synthesizers, you'd have these guys.)
- Bon Voyage (the Starflyer 59 side project), though they switched to Synth Pop on their most recent album.
- Candy Claws (self-described "dream, dream, dream, dream pop")
- The Chameleons
- Cocteau Twins (Trope Makers and Trope Codifiers)
- Cranes (notably, unlike their more optimistic or atmospheric comrades, they dived completely into nightmarish Post Punk with the absolute creepiest Creepy Child vocals ever.)
- Their recent albums are much more optimistic.
- Julee Cruise
- Dead Can Dance (crossing over into Goth and world music)
- Deftones (a cross between Alternative Metal and Dream Pop, with Shoegazing and New Wave influences)
- Chino Moreno's side project Team Sleep, on the other hand, is mostly Dream Pop.
- The Delays
- Dif Juz (a completely instrumental band)
- Galaxie 500
- Iamamiwhoami (Dream Pop + Shoegazing + Concept Video)
- Lisa Germano
- Mazzy Star
- Mercury Rev (dream pop, but with influences from Noise Pop and Psychedelic Rock)
- Mojave 3 (formed by ex-Slowdive members, dream pop crossing over into sadcore and alternative country)
- This Mortal Coil (not technically a "band", see above explanation; also Trope Codifiers)
- Owl City
- The Passions
- Radiohead, while nominally Alternative Rock have occasionally shown influences from it, such as on "No Surprises", which is both Dream Pop and Art Rock.
- Red House Painters (a combination of dream pop and "sad-core", with more slow drawn-out compositions that stay mostly relaxed with really depressing lyrics to boot.)
- School Of Seven Bells
- All Shoegazing bands can be associated with dream pop due to the latter's influence on the former and some overlap between the two genres. For some it's reasonable (Slowdive, which later evolved into the aforementioned Mojave 3, possibly Starflyer 59), for others it's just too much of a stretch (My Bloody Valentine are pure shoegazing, Lush had their moments but too few to actually call them dream pop, Ride moved into different territory later on).
- On that note, Asobi Seksu switched to dream pop on their third album after two albums of imitating My Bloody Valentine. Apparently they were just tired of imitating MBV and wanted to try something else.
- Sigur Rós (dream pop + Post Rock)
- The Sundays (debatable, some people claim they are just a more laid-back version of The Smiths)
- The xx are fairly modern, but unmistakably dreamy, breathy, and beautiful.
- The album Enchant by Emilie Autumn is basically a mix between this and Baroque Pop.
- even the more arrangement-heavy dream pop bands like the Cocteaus stuck to the standard guitar-bass-drums-keyboards lineup; only This Mortal Coil really used string sections, and even they stuck to minimal arrangements instead of overproduction