Heavy metal is two things:
1. Heavy as fuck
2. Metal as fuck
That is, it sounds like a boulder bring dropped on a freight ship and slowly crawling down the side, scraping against the metal deck as it drags the ship to its doom.
Bands that sound like this include but are not limited to:
- Black Sabbath
- Iron Maiden
- Judas Priest
- Motorhead
- Amon Amarth
- Decapitated
- Necrophagist
- Blind Guardian
- Iced Earth
- Angra
- Orange Goblin
- Nekrogoblikon
- Candlemass
- Death
- Manowar
- Warbringer
- Heathen
- Dark Angel
Some musical elements and techniques often evident are:
- Palm muting. This "muting" allows a note to ring out to an extent while some of its frequencies are more or less destroyed. On higher strings, this actually gives a more solid, bright sound, but on lower strings it makes shit heavy as fuck.
- Tremolo picking. Often combined with the above, the aim of tremolo picking to create a volume variance of the same pitch. Since the note is struck repeatedly, its intensity is renewed over and over and over ect. Most common in death and black metal, and somewhat common in thrash.
- Harmonised thirds. To be fair, this is a popular element in jazz and classical, but metal is probably the most prominent use of this in popular music is in metal. And in Iron Maiden. Basically, one guitar player plays a note, and the other guitarist, at the same time, plays a note exactly three scale degrees above it. In the key of A minor, for example, A would be harmonised with C, B would be harmonised with D, C would be harmonised with E, ect. Basically, it creates a major or minor diad (depending on the scale degree) and thickens the sound without actually sounding like a chord.
- Power chords! The simplest chord in the book. Take a note and its fifth scale degree (e.g. E and B) and you have a power chord. They create a kind of dragging sound, and are so harmonically ambiguous that you can play just about any scale over them.
- Heavy distortion. Seriously.
- Technical drumming. Simple drumming can work, but technical drumming just takes up more space in an auditory sense, and thus, it just plain heavier.
- Effective use of bass. Sure, you could have the bass playing root notes the whole time. Or you could use it to be heavy as fuck. Your call.
- Wild soloing. Not necessary, but most metal fans love a wicked solo and thus the musicians deliver.
- Pinch harmonics. Basically a harmonic that a guitarist will shake around to really make it scream. Often used to emphasise a certain note or grab attention. That is, the pinch harmonic is basically a tool of dynamics. Just about impossible without heavy distortion.
- Actually being heavy. There's a difference between being heavy and being harsh. For instance, all hardcore ever is not heavy metal because it is not heavy enough. But it is harsh, but harshness is not a requirement of heavy metal, although it is seen as a virtue in the realm of extreme metal.
- Rocking the fuck out. If you are not rocking, you are doing it wrong.
Anyway, if you use many/most of/all the above, then you are probably playing metal, or at least very metal-influenced rock.
