Approximate listening time: 80 minutes
.. Black Sabbath. They may not have been the first, but they were the first that mattered. In today's terms they're more hard rock than metal, but at the time they revolutionary.
Take note of the guitar rhythms. This pattern becomes a staple.
Black Sabbath - Paranoid https://www.youtube.com/watch?v=96QBXReEQ2k
AC/DC are very much more rock than metal. The important thing to note is the use of Hell themes. While the impact on metal history may not have been huge, as a listener it's important to ackowledge. Hell™ and Satan are okay. It's okay to listen to music with "Satanic" themes, it doesn't make you That Guy. Satan isn't real. It's just shock value.
AC/DC - Hell's Bells https://www.youtube.com/watch?v=ShqkBC9zmWM
Thrash metal is probably the most mainstream of the metal subgenres. It includes the bands almost everyone cites as influences: Metallica, Slayer, Pantera, etc. This is real metal though, it's faster and more harsh than the music that came before. There's also wild guitar solos.
Compare the rhythms and guitar lines to the two songs previous.
Slayer - Seasons in the Abyss https://www.youtube.com/watch?v=DECp8LKurKs
Most thrash metal (including Slayer) is generally not "Satanic". Black metal truly started with Venom and their album "Black Metal". They also used some Satanic themes, but again just for marketing.
Venom - In League with Satan https://www.youtube.com/watch?v=D5wUr4Lut4A
Mobile link (lower quality): https://www.youtube.com/watch?v=jV6j6H4tgOI
Norwegian black metal is the hardcore stuff. We'll work backwards, because early black metal can be hard on the ears. Most of it was recorded and edited by amateurs in bargain basement recording studios. It can be abrasive without some preparation.
Newer black metal is more refined, and some of it's thrash relationships can be more clear.
Note the rock-esque guitar rhythms, but thrashy driving drums. And of course the scratchy black metal vocals.
Abbath - Warriors https://www.youtube.com/watch?v=0R-0ey4kchc
Immortal offer a pretty broad style of music throughout their history and is fairly representitive of the evolution of the genre as a whole. A little more gritty than the last track, but still very obvious thrash roots.
Immortal - At the Heart of Winter https://www.youtube.com/watch?v=3lrS_WaQh1M
At this point there's a pretty sharp jump into the treble-heavy mess of older black metal. There are a couple of things to note here. First, the fast and heavy drumming. Secondly the guitar tone, and lack of clarity. That's not just you, it does sound like white noise. But, as you listen close you'll find the pairing with the drums and bass works in an unexpected way.
Immortal - Blashyrkh (Mighty Ravendark) https://www.youtube.com/watch?v=NP0H491rRFU
From here we leave Immortal, and go to some of the most trve black metal: Burzum. Again, the super treble-y guitars. This is best listened to with headphones, otherwise you'll miss the bottom half of the song.
The slow beat of the drums paired with the wall of guitar noise creates a surprisingly dreamlike atmosphere.
Burzum - Dunkelheit https://www.youtube.com/watch?v=DPyOhP1GTRQ
Burzum - Erblicket die Tochter des Firmament https://www.youtube.com/watch?v=4ZXBEUlJcyM
.. is paved with Gorgoroth albums, mostly?
As we ease into harder Gorgoroth and the more evil metal, we chill out with this nice Gorgoroth intrumental. Note the drums and guitar tones, similar to some of the Immortal above.
Gorgoroth - Heaven's Fall https://www.youtube.com/watch?v=sLW4n4AIHk8
While the guitar tone is more bearable, note the rhythmic similarities between this and Dunkelheit.
Gorgoroth - Sign of an Open Eye https://www.youtube.com/watch?v=73Za2PVVDcI
Now we've gone full black metal. There's no holding back now. We start with a nice french poem.
Gorgoroth - Litani til Satan https://www.youtube.com/watch?v=fFk9XBA0BSo
Behemoth - O Father O Satan O Sun https://www.youtube.com/watch?v=4hVj32UmUyQ
Things get a more aggressive from here on out. Not much more to say other than you should be sufficiently prepared by now. Rock on.
Satyricon - KING https://www.youtube.com/watch?v=ufSb7RORRaU
Behemoth - Ora Pro Nobis Lucifer https://www.youtube.com/watch?v=Cx01fOYsc6E
Do any of the rhythms or melodies in this have any similarity to black metal?
Just some good songs. Optional.
Gorgoroth - Unchain my heart!!! https://www.youtube.com/watch?v=Q0XDTNXRN0Q
Gorgoroth - Carving a Giant https://www.youtube.com/watch?v=_Aib9Z23NnM
Immortal - Cryptic Winterstorms https://www.youtube.com/watch?v=a4Qg69V8aao
Leviathan - Summoning Lupine https://www.youtube.com/watch?v=ZdIrhNPP5Pk