Progressive metal (sometimes known as prog metal or prog-metal) is a subgenre of heavy metal, originating in the United Kingdom and the United States In the 1970s. Progressive metal blended elements of heavy metal and progressive rock, taking the loud "aggression" and amplified electric guitar-driven sound of the former, with the more experimental, complex and "pseudo-classical" compositions of the latter.
Whilst the genre emerged towards the late-1980s, it was not until the 1990s that progressive metal achieved commercial success. Dream Theater, Queensrÿche, Tool and Fates Warning are a few examples of progressive metal bands who achieved commercial success; additionally, Heavy metal bands such as Megadeth incorporated elements of progressive music in their work. Progressive metal's popularity started to decline towards the end of the 1990s, but it remains a largely underground genre with a committed fan base
Progressive metal can be broken down into many sub-genres corresponding to certain other styles of music that have influenced progressive metal groups. For example, two bands that are commonly identified as progressive metal, King's X and Opeth, are at opposite ends of the sonic spectrum to one another. King's X are greatly influenced by softer mainstream rock and, in fact, contributed to the growth of grunge, influencing bands like Pearl Jam, whose bassist Jeff Ament once said, "King's X invented grunge." Opeth's growling vocals and heavy guitars (liberally intermixed with gothic metal-evocative acoustic passages and clean melodic vocals) often see them cited as progressive death metal, yet their vocalist Mikael Åkerfeldt refers to Yes and Camel as major influences in the style of their music.
Classical and symphonic music have also had a significant impact on sections of the progressive metal genre, with artists like Devin Townsend, Symphony X, Shadow Gallery and Ex Libris fusing traditional progressive metal with a complexity and grandeur usually found in classical compositions. Similarly, bands such as Dream Theater, Planet X, Puya, Liquid Tension Experiment, The Faceless, Between the Buried and Me and Animals as Leaders have a jazz influence, with extended solo sections that often feature "trading solos". Cynic, Atheist, Opeth, Pestilence, Between the Buried and Me and Meshuggah all blended jazz fusion with death metal, but in dramatically different ways. Devin Townsend draws on more ambient influences in the atmosphere of his music. Progressive metal is also often linked with power metal, hence the ProgPower music festivals, with bands such as Fates Warning and Conception originating as power metal bands that incorporated progressive elements which came to overshadow their power metal roots.