Los Angeles produced two of the four or five most important thrash bands that ever existed and never produced a scene, and because of that the music it made has been filed for forty years as a footnote to somebody else's chapter. That is a poor way to hear it. Southern California did not make a weaker version of the Bay Area sound. It made a different one, out of different instincts, and the two of them disagree at nearly every point where a decision had to be taken.
What follows sets them against each other on the things you can actually hear: tempo, the shape of a riff, what the lead guitar is for, where the drums put their weight, and what the words are about. The city that got there first is treated here as the control, because the argument is clearer that way round.
Two hundred miles and two different tempos
Start with speed, because Los Angeles took it further and took it there sooner. Slayer ended Reign In Blood in 1986 with a record that runs twenty nine minutes across ten songs, and the tempo on Angel Of Death is not a Bay Area tempo at all: it is a headlong, unmodulated sprint that abandons the groove instead of riding it. Dark Angel pushed harder still. Darkness Descends, released on Combat in 1986 with Gene Hoglan behind the kit, packs more riffs into a single song than an Exodus album spends on a side, and it does not stop to let any of them land.
The East Bay wrote fast songs with slow parts in them. That is the structural difference and everything else follows from it. A Bay Area song of the same years opens at mid tempo, accelerates, then drops around two thirds through into a half time riff the room can move to, and the drop is the point of the exercise. Los Angeles treated the drop as a loss of nerve. Where the East Bay built a mechanism a crowd could operate, Southern California built a wall and ran at it.

What a solo is for
The clearest fingerprint is the lead guitar, and the two cities used it for opposite purposes. The Bay Area harmonised: two guitars in thirds over a fast rhythm, a melodic gesture inherited from the British bands, written out and rehearsed until it locked. Los Angeles refused that almost entirely. Jeff Hanneman and Kerry King played leads that dive, scrape and detonate, whammy bar hauled down to the body of the guitar, atonal where a Bay Area lead would have resolved, and they very rarely played them together.
Both approaches are deliberate and neither is incompetence. A harmonised lead tells a listener the band has a plan. A Slayer solo tells a listener the plan has failed and something is coming through the wall. What Los Angeles gave up in melody it bought back in menace, and the trade is the single loudest difference between the two catalogues.
Megadeth stand apart inside their own city on exactly this question. Dave Mustaine wrote leads that are technical rather than either melodic or atonal, all serrated edges and unexpected intervals, and on Peace Sells... But Who's Buying? in 1986 he and Chris Poland played lines with a jazz musician's sense of where a phrase ends. That is not a Bay Area habit and it is not a Slayer habit. It is a third thing, made in Los Angeles by a man who had been thrown out of a band in Los Angeles and had every reason to prove something.
| Decision | Bay Area | Los Angeles |
|---|---|---|
| Song shape | Fast, with a half time drop written in | Fast, and faster, with no relief |
| Lead guitar | Harmonised in thirds, written and rehearsed | Atonal, whammy heavy, played alone |
| Riff material | Chromatic walk over a pedal note | Tritones, dissonance, riff density |
| Double kick | Punctuation between riffs | A continuous floor to build on |
| Vocals | Barked high, phrased with the riff | Shouted or shrieked, phrased against it |
| Words | Nuclear war, addiction, the news | Death, war crime, the occult, damnation |
| Fed into | Groove metal and the 1990s survivors | Death metal, black metal, grindcore |
The drums decided the next twenty years
Dave Lombardo and Gene Hoglan did something in Southern California that the East Bay never attempted: they made the double kick continuous. Tom Hunting and his peers used the second pedal as punctuation, a burst of six or eight notes to shove a section forward and then off it again, and that restraint is audible on every Bay Area record of the decade. Lombardo laid the double kick down as a floor and played the rest of the kit on top of it.
Every extreme genre that came afterwards took the Los Angeles answer and none of them took the Bay Area one. Death metal is built on a continuous kick. So is black metal, so is grindcore, so is everything that followed them, and the line runs from Hell Awaits in 1985 straight through Florida and Stockholm and Norway without passing through Berkeley at all. The East Bay's influence went the other way, into groove, into Machine Head and Pantera's neighbours, into music that kept the half time drop and threw the speed away.
A harmonised lead tells a listener the band has a plan. A Slayer solo tells a listener the plan has failed and something is coming through the wall.
What the songs are about
The lyrics divide as cleanly as the guitars. The Bay Area wrote about the world it lived in: nuclear anxiety, addiction, the news, the corruption of institutions, the pit itself. It is a journalistic instinct, and even at its most lurid it is pointing at something outside the window.
Los Angeles pointed inward and downward. Slayer's subject was atrocity, damnation and death handled without commentary or moral, delivered flat, as testimony rather than protest, and it was that refusal to editorialise that made the band genuinely frightening in a way no amount of speed could have managed on its own. Dark Angel's world is apocalyptic and airless. Megadeth are the exception again, closer to a political cartoonist than to either camp.

Which city was right
Both, on different questions, and the fair verdict is that Los Angeles made the more extreme music and the Bay Area made the more durable scene. The single greatest thrash record of the decade was made in Southern California and almost nobody would seriously argue otherwise. The forty year careers, the reunions that still sell out, the second and third generations of bands who learned the style from the source, all of that is northern, and the reason is the one thing Los Angeles could never build: twelve bands inside twenty minutes of each other, standing on the same stages, watching each other work.
That, and not the riffs, is why the story is usually told from the north. Where those stages actually were, and what each of them did to the music played on it, is the subject of The Stone, the Keystone and the Rest of the Circuit, and it is the ground floor of this part of the history.