"Here come, here come, here come the Noise Marines!"
"My Emperor's Children, what wonderful music they make."
"Gonna fight the war, AND USE MY MUSIC AS A WEAPON!"
"Oh well; at least it's not Skrillex..."
- – Final thought of an unnamed Planetary Defense Force trooper
Yeah, so Slaanesh is the God of Excessive Pleasure: lots of sex, lots of drugs, lots of weird sex, lots of pain, lots of weird sex that's painful, lots of weird sex while on drugs that are painful. You get the picture. So when it comes to making up a Slaaneshi flavor of Chaos Space Marines, what does GW come up with?
Rock stars, naturally. Rock stars with sound-laser guitars. Because in the '80s, everything was glam' rock and awesome. They've since moved away from giving them actual sonic guitars in favor of sonic guns, but the parallel is still there. Why have they moved away from something freaking awesome into something just kind of meh (excluding the fact that Blaster-Guitars-Swords sound wonderfully dumb)?
Because Games Workshop doesn't know a good thing when it sees one. You really should know this by now. The recent Vigilus Weekender revealed a celebratory model based almost entirely on the original model, with some added flair and modernized scaling. Also with the bonus of it standing on a decapitated Primaris Marine's head.
Even more recently, thanks in part to Dawn of War 2: Retribution and a certain Youtube video This one is even better they've seen a slight resurgence of popularity. The goofy idea of '80s, Motley Crue-spewing Noise Marines has been replaced with the goofier idea of evil-DJ-esque Noise Marines with long and loud sustained "music" (also known as dubstep) being blasted out of speaker-guns at head-fryingly loud volumes. Also the idea of a Land Raver is pretty cool too. Their in-game counterparts, however, still stick true to the original Noise Marines and attempt to rock their enemies to death.
There have been sightings of the Noise Marine's 21st century counterparts who used weaponised dubstep to fuck up Counter Strike wannabes; if you want to make an ACTUAL terrorist's teeth explode, then you need to called up the L.R.A.D, a real world sonic cannon with a range of over two miles, with a total volume slightly lower then a shotgun going off next to your ear, but able to just keep that volume up for hours.
L.R.A.D is maybe close, and while it surely does please Slaanesh while doing a pretty awesome job of ruining some terrorist's day, it does not quite match the mark of Slaanesh's rock star/Skrillex Marines, but some day...
If you want to field old style rock star Marines, redesign be damned, you're in luck. Spellcrow makes conversion bits for both guitars and arms.
Dawn of War 2
Noise Marines are scary as fuck in Dawn of War 2. 3 member squad carries 3 sonic blasters that does flame damage; yeah, 3 flamers in one squad. Their damage is quite high, even hurts heavy infantry like Tactical Marines. The result is even better if you use it on light infantry like Guardians, Shoota Boyz or Termigants. But that's not all!. Sonic blasters disable ranged weapons and grenades on those hit. So you can't just out-shoot them, they will also disable your weapons. You could try to get into melee with them...but they have an ability that knocks back everything short of vehicles in a wide radius of their position so your choppy troops will just bounce around aimlessly for any other troops to finish off.
They are even more threatening in tier 2 with their Blastmaster upgrade. Basically it's a plasma cannon for Chaos army. Does great damage, insane range, massive knock-back. The weapon is a bit odd however, as it knocks back everyone in its firing path. So if you set up your Havocs to fire in front of them, they will be INTERRUPTED by a Blastmaster. The weapon is great for crowded groups.
Noise Marines are all Chaos was missing in Chaos Rising expansion pack. Flamers for power bashing, artillery for later stages. Their short range sonic blasters may become a problem in later stages since there will be lots of threats for them and they are in front of your all army with their short range. Upgrading them to Blastmaster wouldn't be a bad idea for protecting a victory point.
On the Table Top
These guys are so good now! In their previous incarnation while an all around solid choice, but they had mobility problems, as most of their set up forced you to play in a very static fashion. Well, Slaanesh heard our pleas, and THINGS SHALL GET LOUD NOW! Sonic Blasters are now Assault 3, so you not only can move, but you have even the option to advance and still shoot (with a -1 to hit, but still!); they're broadly speaking more expensive combi-bolters, doubling the price in exchange for ignoring cover and moving from Rapid Fire 2 to Assault 3. Blastmasters are not as powerful as they once were against power armor; but are far better against characters, terminators, vehicles, and multi-wound models in general. Averaging 2 shots at S8/AP-2/D2, but possibly doing 9 damage in a single shooting phase, at 20 pts they cost 5 pts less than a Missile Launcher or Lascannon! The Varied Frequency setting will see far more use than in the past as well; averaging 3.5 S4/AP-1/D1 shots, with the potential for 6 shots, it's got slightly better rate of fire than a Sonic Blaster, and a much-improved AP of -1. The Doom Siren is now a heavy flamer with AP-2 and D6 auto-hits for 10 pts. You can now take a Sonic Blaster on your champion! They get the Music of the Apocalypse rule, which lets them fire their weapon (or a grenade) when they die, even if they are in melee. This rule doesn't seem to let you fire on the unit you are in melee with, though. Noise Marines are not slouches in the melee either with 2 attacks each. Which makes them as effective as loyalist Assault Marines in melee. You can swap out their bolters for Chainswords to gain a bonus attack taking them to 3 attacks each in the fight phase. Take the Icon of Excess and the trigger Death to the False Emperor on a 5+ to hit. The unique Emperor's Children stratagem: Excess of Violence give them a bonus attack for each model slain. They're no Khorne Berserkers but melee kitted Noise Marines can do work with the right stratagem and psychic power boosts. All in all, these guys are awesome (and surprisingly cheap at 15 pts, too).
- Note: The rule that protects characters from being directly targeted specifically states it only applies to the shooting phase. So, if you have Noise Marines die in the psychic or fight phases, Music of the Apocalypse will let you target characters regardless of nearby units!
- Fun quirk with the Champion: It is technically possible for the Champion to take a Sonic Blaster, a Doom Siren, AND a combi-bolter, and can legally fire them all at once!
- New FAQ note: Death to the False Emperor applies to any hits made in the Fight phase, including shooting attacks made with pistols and sonic weapons (Icons of Excess are truly decadent now). Grenades can also be thrown by EVERY Noise Marine that dies, not just one per unit. The potential suicide-bomber strategies are mind blowing! Due note however that only pistols can be fired at units within 1", which means no drowning the unit that's murdering your boys in NOISE, so it's a good thing they don't have to be the target of your SWEET CACOPHONY.
- Additional FAQ Note: If you go the close combat route with your Noise Marines (possibly even if you don't), give your Champion a Plasma Pistol. If you use it on your Music attack, there's no reason not to supercharge it--you're dead anyway, and might even get an extra DttFE shot off!
Tl;dr: The God of Excess delivers in the 8th Edition. While briefly losing their ability to be taken as troops when the codex first dropped, a subsequent FAQ has allowed to be taken as troops if they are Emperors Children. Slaanesh in general is just excellent this edition. Now that Sonic Blasters are Assault 3 you can foot slog them to a mid-field objective and still maintain effective fire. Or take a squad of Noise Marines in a Metal Box, get it within range of a distant one, and drop the bass. In an Emperor's Children detachment they gain Flawless Perfection granting them always strikes first in combat. In a Renegade detachment they Dark Raiders which allow them to move, advance and charge in the same turn. So they can move and advance, fire off 3 sonic Blaster shots, and charge into combat. With all the newly available psychic powers and stratagem combos of the new codex.