What is progressive metal? I mean, what makes it "progressive" or whatever. When I hear of 'progressive' I instantly think of crazy time sigs and keyboards/synth.

and this is a pretty newbish question, but do you NEED keyboards/synth in a prog metal band?

What are some basic "stuff" included in writing prog metal riffs? :/

^^ Sorry for my bad english. :P

"Progressive" means "forward-thinking". It can also mean "rip off other 'foward-thinking' bands" "abandon traditional song structures and make up your own". I've found progressive metal just has more thought put into the songwriting.
No, you don't need keyboards in a Prog Metal band. I'm not really sure what makes a band 'progressive metal'. Everywhere I look it says stuff like odd time signatures and complex riffs. As for writing prog metal riffs... They really aren't any different than normal metal riffs. Just make sure that there are a lot of them and they aren't repeated too often. And don't use conventional song structures.
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Progressive metal, as a description, is metal with progressive songwriting. That is, song structures often progress; instead of verse-chorus-verse-solo-chorus et cetera, you'd come up with an idea and evolve it. You may end up progressing elsewhere into an entirely different theme. It's more about structure, than anything.

Progressive metal, as a genre, is occasionally regressive in that it copies what's been done before.

So if you want to write progressive music in a metal style, listen to how some of the bands structure their songs, see how the parts are laid out.
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^ That's true regarding the copying. There are a fair number of bands that copy the stylistic elements of Dream Theater and other progressive juggernauts.

Overall that's a good point - within progressive metal song structures, bands generally spend considerably more time on one musical idea than another band would, leading to generally longer song lengths. Either that, or they play a riff for 5 seconds and then never repeat it again for the entire 20 minute long song.

Progressive metal also focuses on the technical aspects of playing, whether it be by playing complicated harmonies at a quick tempo, or playing in unconventional rhythms and time signatures. You certainly don't need a synth in a metal band. Consider bands like Meshuggah or Cynic - bands on pretty separate ends of the musical spectrum, yet neither one with a keys player. On the other hand bands like Dream Theater and Symphony X rely on keyboards to provide both backing ambiance, riffing and prominent melody lines. The variation of sounds under the "progressive metal" umbrella is really wide, so it's hard to give a straight-forward categorization.

In terms of "what kind of stuff goes into a prog metal riff", I would agree with "think outside the box". Not much else that's consistent between them. If you're looking for some sort of generic progressive metal riffs, just listen to any of the aforementioned bands and see for yourself. If you're looking to truly go on a song-structure exploration, I would strongly suggest the album Colors by Between the Buried and Me.
Last edited by alexbass at Oct 11, 2011,