The styles of underground music range from the 1960s psychedelic music of the US hippie counterculture, to the DIY anti-corporatism of 1970s-era punk rock, to 1990s and 2000s-era experimental electronic music.
While the term comprises a range of different musical genres, they typically share common values, such as the valuing of sincerity and intimacy; an emphasis on freedom of creative expression; and an appreciation of artistic creativity. As well, while very few types of underground music are completely hidden—except perhaps the underground rock scenes in the pre-Gorbachev Soviet Union—the performances and recordings may be difficult to find for outsiders. Some underground musical genres never left their non-mainstream roots, such the jagged, aggressive UK 82-style hardcore punk bands such as Discharge. Some underground styles eventually became mainstream, commercialized pop styles, such as underground hip hop of the early 1980s, which eventually became a popular, mass market musical style in the 2000s. In the 2000s, the increasing availability of the Internet and digital music technologies made underground music easier to distribute using streaming audio and podcasts. Some experts in cultural studies now argue that that there is no underground because the internet has made what was underground music accessible to everyone at the click of a mouse. One expert, Martin Raymond, of London based company The Future Laboratory commented in an article in The Independent, saying trends in music, art and politics are:
... now transmitted laterally and collaboratively via the internet. You once had a series of gatekeepers in the adoption of a trend: the innovator, the early adopter, the late adopter, the early mainstream, the late mainstream, and finally the conservative. But now it goes straight from the innovator to the mainstream.
In effect, this means a boy band (for instance) could be influenced by (formerly) obscure 1960's garage rock, early 1980's post punk, noise rock acts like Pussy Galore or even composers of avant-garde classical music like John Cage and Karlheinz Stockhausen and still remain recognisable as a boy band.
Shlomo Sher's "philosophy for artists" argues that there are three common misconceptions about the "underground": that it refers exclusively to the rave/electronica scene; that it can be described with a vague, broad definition of "anything which is not mainstream"; and the myth that underground music is kept secret; he points out that no band or performer "exclud[es] virtually anyone or anything" using "secret passwords and hidden map points". Instead, Sher claims that "underground music" is linked by shared values, such as a valuing of grassroots "reality" over music with "pre-wrapped marketing glossing it up"; sincerity and intimacy; freedom of creative expression is valued over commercial success; art is appreciated as deeply meaningful fashion; and the Underground "difficult to find", because the scene hides itself from "less committed visitors" who would trivialize the music and culture.
In a Counterpunch magazine article, Twiin argues that "Underground music is free media", because by working "independently, you can say anything in your music" and be free of corporate censorship. The genre of post-punk is often considered a "catchall category for underground, indie, or lo-fi guitar rock" bands which "initially avoided major record labels in the pursuit of artistic freedom, and out of an 'us against them' stance towards the corporate rock world", spreading "west over college station airwaves, small clubs, fanzines, and independent record stores. Underground music of this type is often promoted through word-of-mouth or by community radio DJs. In the early underground scenes, such as the Grateful Dead jam band fan scenes or the 1970s punk scenes, crude home-made tapes were traded (in the case of Deadheads) or sold from the stage or from the trunk of a car (in the punk scene). In the 2000s, underground music became easier to distribute, using streaming audio and podcasts Punk rock was an underground musical form when it first developed in the mid-1970s, as was its descendant,UK 82-style hardcore. UK hardcore bands from the early 1980s such as Discharge eschewed major labels.
Even some musical styles that eventually became mainstream, commercialized pop styles started out as underground music. Late 1970s disco is often considered to be a very commercialized type of pop music. However, before disco's mainstream adoption in 1977 and 1978, disco records were underground music created by nightclub DJs for the gay dance club scene. Similarly, hip hop began "on the streets"; in the early 1980s, rappers did beatboxing and made up rhymes for tiny underground labels. Genres such as alternative rock, grunge, various forms of heavy metal, grindcore, electronica, outsider music, and experimental music, also trace their roots to underground scenes.
A music underground can also refer to the culture of underground music in a city and its accompanying performance venues. The Kitchen is an example of what was an important New York City underground music venue in the 1960s and 1970s. CBGB's is another famous New York City underground music venue claiming to be "Home of Underground Rock since 1973".