On symphonic metal and song structure
Let’s consider Therion, or more specifically, how they changed from their early death metal days to their symphonic grandeur.
Compare “Asphyxiate with Fear” off their debut to what may very well be their signature song, “To Mega Therion“. Since you can’t talk to me AS I write this post, I expect you to listen for the differences in structure.
The first one eschews most accompaniment for monophonic phrases of considerable complexity strung together in a relatively through-composed fashion – isn’t that AWESOME?
The second one takes some basic traditional/power metal stylings, puts them in cyclic songs with obvious choruses and verses and such, and dresses it up by polyphonizing everything, ornamenting things, and for good measure, an operatic choir. Isn’t that AWESOME?
This, I believe, shows us what happens when you attempt to put an orchestra into your music. It happened to Haggard, it happened to Dimmu Borgir, and if I try to compose with an orchestra, you’ll probably see it happen to me, too. It even happens with classical music. If people are writing orchestral arrangements, are they going to attempt to produce 12 minimalistic death metal songs that harmonize with each other when played together? They might, but it’d be extremely difficult to get them to not only sound good, but be relatively distinct. It seems that there’s only so much polyphony that any given composer is willing to attempt, so when the amount of instruments being written for spirals out of hand, the amount of voices on average is going to stay the same, or at least, not drastically rise. Using the example of Therion, “Asphyxiate” has one major “melody”, with drumlines. Occasionally, a guitar solo shows up, or keyboards at the end. “To Mega Therion”, on the other hand – a melody and harmony – the phrases are simpler, shorter, but layered on top of each other. I’d use the term “serialism” to describe the former, but it’s already taken. Polyphony and monophony and homophony will have to suffice.
Incidentally, the latter approach may disgust some metalheads, who don’t want their riffs reduced in number and complexity, even in exchange for more harmony and backing.