Progressive Metal is a subgenre of progressive rock as much as it is a subgenre of heavy metal, and this is how its sound is defined: a blend of heavy, guitar-oriented metal music enriched with compositional innovation and complex arrangements, usually expressed through diverse instrumentation and often (but not always) with odd-time signatures. Common, but not essential to define the movement, are the frequent use of keyboards, high-pitched vocals, concept lyrical themes and tracks of longer duration. Similar to progressive rock, progressive metal draws influences from other genres, such as jazz/fusion, ethnic, classical and symphonic music. The heavy sound of some of the progressive rock bands of the 70's has been one of the building blocks on which progressive metal was raised. Progressive rock pioneers such as King Crimson and Rush have often been acclaimed as the main influences of progressive metal bands. The other major influence has been the NWOBHM (New Wave of British Heavy Metal) movement, and especially the twin-guitar arrangements of Iron Maiden, which have left their stamp on the early stages of the genre's development. The pioneers of the subgenre, often (and not unjustifiably) referred to as the "Big Three" of progressive metal, are Queensrÿche, Fates Warning and Dream Theater. They all have set the scene of what was to follow in the movement. The defining era for the genre was the second half of the 80's, among Queensrÿche's "The Warning" (1984) and (most explicitly) "Rage for Order" (1986) along with Fates Warning's "Awaken the Guardian" (1986) and "No Exit" (1988) releases. The former evolved on their pure American power metal beginnings, while the latter refined their technical/NWOBHM-influenced metal into more progressive forms. Although producing demos since the mid-80's as Majesty, Dream Theater's first release came in 1989 with "A Dream and Day Unite". The innovative use of keyboards along with influences from American heavy/power metal and progressive rock produced an original blend which was to be further refined in 1992's "Images and Words", which until this day remains next to Progressive Metal definition in any musical dictionary.
Queensrÿche-Suite sister Mary (Operation: Mindcrime, 1988 USA)