One of the most important innovations of the 1990s in the canon of psychedelic folk-rock was "slo-core". Variously defined depending on local flavors, it basically referred to a slow, dreamy, melancholy version of dream-pop. It was a direct descendant of Galaxie 500 and Yo La Tengo that typically manifested itself via lengthy and subdued compositions.

Slo-core was sanctified in Chicago by Codeine (11) with Frigid Stars (jun/aug 1990 - ? 1990). John Engle's guitar distortion was so dilated it sounded like an organ, Chris Brokaw's drumming evoked bells tolling for a funeral, and Stephen Immerwahr's sleepwalking litanies evoked Nick Drake and Tim Buckley. That emotional "black hole" attained nirvana with White Birch (aug/dec 1993 - mar 1994), featuring new drummer Doug Scharin, thanks to longer songs, deeper trance and slower tempos, as if they were aiming for a song with no title in which the group does not play and does not sing.

North Carolina's Seam (12), the project of former Bitch Magnet's vocalist Sooyoung Park, fashioned the floating timbres and shimmering textures of Headsparks (aug 1991 - mar 1992) but, more importantly, the unstable filigree of The Problem With Me (? 1993 - aug 1993), a sedate but also forceful work that seemed to merge tender folk-pop and neurotic hardcore, and felt like the slow-motion replay of a volcano's eruption. Are You Driving Me Crazy? (jan 1995 - jun 1995) was both an even more personal show of the leader and a less abstract, almost "poppier" affair, which led to the atmospheric melodies of The Pace Is Glacial (dec 1997/jan 1998 - sep 1998).

San Francisco's Red House Painters (111), an acoustic quartet led by introverted poet Mark Kozelek, penned the depressed mantras of Down Colorful Hill (? 1989/? 1991 - sep 1992): shy guitars that played chords as if they were reciting rosaries, and moribund dirges that seemed to end before beginning but then lasted for eternity, creating quietly unnerving atmospheres that blurred the border between sorrow and ecstasy. Like with the music of Leonard Cohen, Tim Buckley and Nick Drake, the effect was both subdued and majestic, a contradiction that became the quintessence of their art. The demo-quality of those recordings contributed to the sense of philosophical melancholy, but Red House Painters (sum 1992/spr 1993 - oct 1993), also known as Rollercoaster, revealed a much lighter and brighter mood: rather than whining, Kozelek was contemplating the universe. Each song was a moment in time, an impressionistic watercolor. Ocean Beach (? 1994 - mar 1995) brought even more life to the compositions, dispensing with the most austere elements of their slow acoustic chamber folk. Mark Kozelek's next project, Sun Kil Moon, interpreted Kozelek's existential spleen in the 14-minute cryptic tour de force Duk Koo Kim, off Ghosts Of The Great Highway (? ? - nov 2003), and especially in the sprawling streams of consciousness of April (mar/aug 2007 - apr 2008).

Minneapolis' trio Low (15) also resurrected the depressed and anemic mood of Nick Drake, but then wed it to LaMonte Young's droning minimalism and to the Cowboy Junkies' lounge melodies. I Could Live In Hope (fall 1993 - feb 1994) was the quintessential case of "the whole is more than the sum of its parts": the parts were trivial and scant, but the whole was a triumph of unbridled creativity. Ascetic more than mournful, it sounded like the rock equivalent of Japanese haiku and Tibetan tangka, an art of frigid ballads that drowned in a lattice of empty notes. Low's "song" was chamber music for emotions that slowly faded away, that were never truly felt. At the same time, the unbearable delay and dilation of musical structures fostered and maintained an intensity of feeling that an ordinary refrain would have released in a few seconds. The tranquil jams of Long Division (nov 1994 - ? 1995) were as musical as circles spreading in a pond, but were given a soul by the whispered thoughts of guitarist Alan Sparhawk and drummer Mimi Parker. The Curtain Hits The Cast (jan/feb 1996 - aug 1996) turned to electronic keyboards in order to relieve the gloom and lighten up the ambience, and Secret Name (nov 1998 - apr 1999) expanded the instrumentation by adding a string section, piano and timpani. Low regressed to a more conventional format for Things We Lost In The Fire (? 2000 - jan 2001) and attained formal perfection with Trust (? 2002 - sep 2002), a masterpiece of subtle metamorphoses, glacial counterpoint and ghostly religious music.

Brick Layer Cake, the project of veteran Minneapolis drummer Todd Trainer, bridged slo-core and post-rock on Tragedy-Tragedy (? ? - oct 1994).

Texas' Bedhead (2), led by Matt Kadane, explored a state of mind between psychedelic trance and teenage angst on WhatFunLifeWas (jun/sep 1993 - apr 1994) and Beheaded (jul 1995 - jun 1996). Their ameobic pieces "grew" rather than simply existed: they were the object of a gradual, evolutionary (and potentially never-ending) process that slowly brought the emotions into focus.

Ethereal pop, 1990-93

A variant on "male" slo-core was a style of fragile folk-pop ballads for female whispers and understated arrangements, more or less inspired by the Cowboy Junkies.

The concept was pioneered by a group that originated from the psychedelic movement, Mazzy Star (2). Guitarist David Roback of Rain Parade and Opal replaced Kendra Smith with a more delicate vocalist, Hope Sandoval, and greatly expanded the scope of his music on She Hangs Brightly (? ? - may 1990), a melting pot of acoustic folk, Delta blues, oneiric acid-rock and laconic lounge jazz. So Tonight That I Might See (? ? - sep 1993) barely increased the melodic element of their tender lullabies, which reached alternatively for the galactic, subliminal, mystical and impressionistic levels.

Somewhat related to this atmospheric and psychological school were the electronic vignettes of His Name Is Alive (3), the brainchild of Michigan's multi-instrumentalist Warren Defever who employed different female singers for each album. Rhythm was optional on Livonia (? 1985/? 1990 - jun 1990), an experimental work that indulged in tape loops and samples but mostly relied on an elegant combination of ghostly neoclassical vocals and surreal electronic effects. Guitars were given more prominence on Mouth By Mouth (? 1992 - apr 1993), and the group sound was more earthly, bridging Laurie Anderson's musical theater and dream-pop. The sophisticated, almost ambient Stars On E.S.P. (? 1992/? 1995 - jun 1996), was reminiscent of Brian Wilson's productions but in a skewed, unorthodox way. Defever's arrangements did not shun the obvious: they recreated the obvious in another dimension.

Illinois' Moon Seven Times (1), featuring Lynn Canfield, specialized in ethereal madrigals that boasted the spiritual depth of a raga on Moon Seven Times (? 1990 - jul 1993).

Congo Norvell, led by former Gun Club's guitarist Kid Congo Powers and vocalist Sally Norvell, gave one of the best imitations of the Cowboy Junkies with their Lullabies (? 1991/? 1992 - feb 1993).

The atmospheric ballad, 1990-94

Whether it was slo-core or simply "slow pop", whether the influence of alt-country or a by-product of psychedelia, the slow, atmospheric ballad became fashionable again in indie music.

Los Angeles' Idaho (2), i.e. singer Jeff Martin and guitarist John Berry, were both the most existential and the most psychedelic. Year After Year (? 1992/? 1993 - sep 1993) was a set of suicidal psalms imbued with documentary lyrics and recited in a pensive tone halfway between Leonard Cohen and Lou Reed. Martin's indolent pessimism reached new heights of sweetness on This Way Out (spr 1994 - oct 1994).

Acetone (1) continued the tradition of (in reverse chronological order) Dream Syndicate, Television, Neil Young and Grateful Dead with collections of transcendental pseudo-country ballads such as Cindy (apr/jun 1993 - oct 1993).

Pennsylvania's acoustic quintet Low Road (1) wed the aesthetic of slo-core to country music on The Devil's Pocket (? 1990/? 1994 - oct 1994).

Los Angeles' Love Spirals Downwards concocted a gothic/exotic/medieval/spiritual variant of the dream-pop cliches made popular by the Cocteau Twins and Dead Can Dance, for example on Ardor (? 1994 - ? 1994).

Seattle's progressive ballad, 1993-94

Seattle (and the Northwest in general) originated a close relative of "slo-core", a form of "textural rock" that hanged somewhere between the extremes of roots-rock and post-rock, and emphasized non-linear guitar-based soundscapes. Built To Spill (13) were the reigning champions of the genre throughout the decade. Formed in Idaho by guitarist Doug Martsch, with Caustic Resin's guitarist Brett Netson and Lync's rhythm section, Ultimate Alternative Wavers (fall 1992 - may 1993) was mostly a guitar tour de force, but already displayed their slovenly, messy and noisy fusion of Neil Young, Grateful Dead and Sonic Youth. There's Nothing Wrong With Love (may/jun 1994 - sep 1994), instead, focused on structure, constraining Martsch's imagination. Perfect From Now On (? 1996 - jan 1997) summed the two, granting the guitar several degrees of freedom while anchoring it to a spectacular group sound (the Spinanes' drummer Scott Plouf, Nelson's bass, cello, mellotron and synthesizer). These articulate and elegant compositions relied both on lengthy hypnotic jamming and on simple, manageable form. Martsch's relentless guitar ruminations created the noise-rock equivalent of John Fahey's "primitive guitar": introspection, meditation on the meaning of life, contemplation of the universe, and worship of the absolute. Keep It Like A Secret (nov 1997/may 1998 - feb 1999) simply channeled that creative force in the format of the rock song. When Built To Spill finally returned to the science of abstract jamming, on You In Reverse (? 2004 - apr 2006), its blend of pensive transcendence and manic depression sounded like the perfect soundtrack for the zeitgeist of the new century. Martsch's guitar had a unique way to penetrate the inner core of a song's melody, and transform it into a cathartic experience. Marstch's tormented solos were the antidote to an era that increasingly strived for simplicity and superficiality.

Silkworm (2) boasted the depressed noise of guitarists Joel Phelps and Andy Cohen. Cohen's introverted mood and neurotic guitar dominated In The West (mar 1993 - jan 1994) and Libertine (may 1994 - aug 1994). Pared down to a trio after Phelps' departure, Firewater (? 1995 - jan 1996) veered towards the distorted, metaphysical folk-rock of Dream Syndicate and Neil Young, while highlighting the creative rhythms of drummer Michael Dahlquist and bassist Tim Midgett. Developer (? ? - apr 1997) was another subtle essay of musical imagery, and perhaps even more arduous.