Jackson Signature Sleep Token IV Monarkh review

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What is it?

Despite never showing his face or speaking publicly, Sleep Token’s IV is amongst the most searched metal guitarists of the past few years. The Roman numeral-ordered quartet is arguably the biggest band in metal right now, so it was only a matter of time before IV got a signature guitar. The Jackson Pro Plus Series Signature Sleep Token IV Monarkh SC is the resultant offering, and if the popularity of the band is anything to go by, it could end up being one of the most popular metal guitars ever made.

With the band hell-bent on maintaining anonymity, details of his sound were scarce until a few years ago, when Sleep Token’s guitar tech revealed all the gory details. IV’s signature model comes from the lineage of that Jackson guitars Custom Shop Monarkh, which certainly turned my head when it was announced back in late 2023. That was an 8-string guitar, though, whereas this is a Bass IV.

(Image credit: Future)

There are likely some players who will be disappointed this isn’t the same 8-string IV has been wielding on tour for the past few years, but this guitar isn’t as far away from that as it looks at first glance. Both carry a 30-inch scale length, featuring a girthy .084 low E. The Monarkh archtop single-cut body is the same, along with that distinctive ‘Pale Moon’ ebony fretboard. Both models also feature luminlay side dots and an EverTune bridge for stability on the low strings.

Specs

A Jackson Pro Plus Series Signature Sleep Token IV Monarkh SC electric guitar — (Image credit: Jackson)

Launch price: $2,299 | £1,949 | €2,299

Made: Korea

Type: Bass VI

Body: Mahogany with maple cap and quilt maple veneer

Neck: 3-piece caramelized maple, set-neck

Fingerboard: Pale moon ebony, dot inlays, 12″ to 16″ compound radius (304.8mm to 406.4mm)

Scale length: 30″ (762mm)

Nut/width: Phenolic, 42.86mm (1.6875″)

Frets: 22, jumbo, stainless steel

Hardware: Jackson sealed die-cast locking tuners, EverTune F6 model with custom saddles

String spacing at bridge: 50.5mm

Electrics: Fishman Fluence Open Core COC-BB1 (bridge), Fishman Fluence Open Core COC-NB1 (neck), 3-position toggle switch, volume (push/pull)

Weight: 7.9lbs/3.6kg

Left-handed options: N/A

Finishes: Transparent Black Burst only

Cases: Jackson gig bag included

Contact: Jackson

Guitar World video demo

Sleep Token Signature Models: Jackson Pro Series IV Guitar & Charvel PM SD1 Bass | First Look & Demo – YouTube

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Build quality

Close up of the Pale Moon ebony fretboard on the Jackson Signature Sleep Token IV Monarkh — (Image credit: Future)

Build quality rating: ★★★★½

The guitar itself looks phenomenal

I’m disappointed with the guitar case the IV Monarkh comes in. Eagerly opening the box, I’m expecting a signature model of such an image-focused band might contain some unique easter eggs or details on its case, but alas, it’s just a standard Jackson gig bag. It doesn’t fit the guitar very well, and considering the cost, I’d have expected at least one of those semi-hard foam cases like the Christian Andreu Rhoads came in.

The guitar itself looks phenomenal. It’s a real stunner with the dark, quilted maple top, but that Pale Moon ebony fretboard is the star of the show. It’s a unique color combination, looking like an almost white maple with near-black ebony streaks across it. The look is natural, from the Diospyros malabarica species often called black and white ebony, and its use means no two fretboards of this model will be the same.

The neck join on the Jackson Signature Sleep Token IV Monarkh electric guitar

(Image credit: Future)

The sharp-eyed will note there’s no Sleep Token logo at the 12th fret, as we see on IV’s Custom Shop 8-string, which again is a little disappointing. Perhaps the cost of the fretboard outweighed that of adding in the additional work to spec a custom inlay of such complexity. For super fans this might be a loss, but for those who just want a drop-tuned metal guitar, it could absolutely be a plus that there’s no obvious ST branding on it, apart from the ‘IV’ on the headstock.

There’s an unsightly block of black gloss that partially covers the neck from the heel

Inspecting the guitar closely, I can find no obvious issues with the build, nor the aesthetic. Everything feels robustly applied, and it’s an exquisitely finished instrument. There’s a belly cut on the back of the body, as well as a slight carve on the cutaway to aid upper fret access.

One odd choice is that there’s an unsightly block of black gloss that partially covers the neck from the heel. Perhaps done to cover up the neck joint, it’s not on the Custom Shop model and feels a little odd terminating diagonally across the maple neck just shy of the 15th fret.

Playability

Close up of the EverTune bridge on the Jackson Signature Sleep Token IV Monarkh electric guitar — (Image credit: Future)

Playability rating: ★★★★☆

It’s impressively playable considering the huge scale

Sitting down to play, my first impression is that it’s impressively playable considering the huge scale and behemoth string gauge (D’Addario® EXL156 Bass VI Nickel Plated Steel .024-.084). All the strings are wound for this monstrous set, yet I find the string tension to be relatively low. I can fret barre chords on it, and bending the strings is absolutely achievable once you set the EverTune to the correct mode.

It’s not super shreddable, purely because of the thickness of the strings. With a bit of practice, I can let rip on it a bit, and adapting my right-hand technique for things like sweeps is possible, but it feels weird initially. This is where those prog metal players might have preferred an 8-string versus the Bass VI we have here.

The back of the body of the Jackson Signature Sleep Token IV Monarkh electric guitar

(Image credit: Future)

The body is quite small, and with the huge scale, I find it a little awkward to play sitting down at my desk. The upper frets feel quite far away, and I find myself stretching to reach them while balancing the guitar on my right leg. I’m 5’ 9”, distinctly average height, so if you’re smaller than me, you’ll definitely want to get this on a guitar strap for more comfortable playing.

I find my hands getting tired at the end of a few playing sessions due to the monster size, especially when trying to play more technical metal. It’s absolutely gigantic in feel, and it’s been a while since I last used an extended-range guitar. There’s a definitive adoption phase needed when switching from a normal-scale guitar to this instrument, so be prepared for some warming up before your hands and arms adjust.

Sounds

Close up of the bridge humbucker on the Jackson Signature Sleep Token IV Monarkh electric guitar — (Image credit: Future)

Sounds rating: ★★★★☆

I find there’s a lot of work needed to tame that low E string

As IV is a Quad Cortex user, it makes sense to test it with some of the Neural DSP plugin suites. While there’s not much info on exactly what amp models IV is using, I opt to use Gojira X and Nolly X, both of which are designed for modern metal tones. But from my initial playing using one of my own presets, I find there’s a lot of work needed to tame that low E string.

It’s very unruly out of the box, so I start with a high-pass filter on the way in to help tame the low end. Next I need to mess with the amp controls, particularly the resonance control on the 5150-inspired amp sim. It’s still a bit much, though, so my last adjustment is to lower the bass side of the humbucker a touch. It helps a lot, and I’m able to get a much tighter, modern metal tone out of it.

If you like heavy music, then this guitar can do it all with the right adjustments. Switching to the neck position is perfect for sludgy doom power chords, whereas the bridge position is ideal if you want to play djent-style tones or more prog metal-inspired stuff. My final fix is to pinch a Gruv Gear fret wrap from my own baritone and place it behind the nut to tame some of the extraneous noise.

Close up of the pickup selector on the Jackson Signature Sleep Token IV Monarkh electric guitar

(Image credit: Future)

I’m really impressed at how well-behaved it is through lower-gain presets and totally clean ones

It’s still not quite as precise for heavy tones as some players might want, and that’s because the pickups themselves are more vintage-voiced. Jackson has opted to fit the Fishman Fluence Open Core Classic pickups rather than the Modern ones, which makes it more versatile overall, but may not satisfy those looking for that super compressed, modern djent tone.

Due to this, it sounds surprisingly good played clean. I’m really impressed at how well-behaved it is through lower-gain presets and totally clean ones. It turns standard chord progressions into really ominous-sounding passages, and I wonder if part of the thinking here with the Classic Fluence was to prioritize flexibility over the often more sterile-sounding modern-voiced Fishmans. It can certainly handle those softer, cleaner Sleep Token moments.

Each pickup has two voices: a modern active and modern passive. Pulling the volume knob up activates the passive mode, which sounds a bit more open and has a more treble response versus the very midrangey active mode. It’s not a huge difference between the two, and the single-coil voice isn’t wired in on this guitar, which would’ve given it a more definitive secondary voice.

Verdict

The Jackson Signature Sleep Token IV Monarkh electric guitar lying on a piece of corrugated metal with a guitar cable coiled nearby — (Image credit: Future)

Despite being the signature guitar for Sleep Token, I think the Jackson IV Monarkh can handle pretty much any modern metal duty. Whether you want Periphery-style djent tones or Loathe-type super-drop tuning, it’s a stable platform for chugging once you make a few adjustments to your signal chain and the guitar itself.

I think the Jackson IV Monarkh can handle pretty much any modern metal duty

It’s surprised me with its versatility, too. It’s not quite as good for low-tuned clean stuff as a baritone, but it’s playable enough to do open and barre chords, and you can get some lovely sounds out of it with the clean channel of your amp alongside some reverb and delay.

For a certain portion of the metal community, however, the gauge of the strings will make it too tough for some playing styles. If you’re looking for a shred guitar that’s tuned super low, this doesn’t provide the slinky playability of an 8- or 7-string guitar, so prog metal aficionados may want to look elsewhere.

Guitar World verdict: If you love drop-tuned metal and want to focus on riffs rather than shredding, the Jackson Signature Sleep Token IV Monarkh is a great alternative to a 7- or 8-string guitar. The pickup choice is flexible enough for djent riffs as it is cowboy chords, and the looks are distinctive enough to make it appealing to ST fans without putting off the wider metal community, who perhaps aren’t so obsessive about the band.

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Ratings scorecard
Test	Results	Score
Build quality	Very well put together, but the paint on the neck joint is ugly	★★★★½
Playability	Surprisingly playable, but difficult to shred on.	★★★★☆
Sounds	Can cover a wide array of tones from modern metal to clean stuff.	★★★★☆
Overall	Not as one-dimensional as it first appears, ideal for modern metal players.	★★★★☆