Review: Quadvium – Tetradōm

Style: Progressive metal, jazz fusion (Instrumental)
Recommended for fans of: Atheist, Cynic, The Omnific
Country: International
Release date: 30 May 2025

The fretless bass is an indispensable tool for tech deathers and fusioners alike. With its otherworldly and smooth timbre, the instrument adds a distinctly heady flavor to any piece. I personally can’t get enough of it, and neither can bassists Steve DiGiorgio (Death, Autopsy, Control Denied, among many others) and Jeroen Paul Thesseling (Obscura, Pestilence) of Quadvium, an instrumental progressive metal group based on the conceit of, “What if fretless bass but more?” On their debut, Tetradōm, DiGiorgio and Thesseling duel and weave around technical fusion passages, but are two Quads better than one?

Tetradōm finds a firm base in 90s technical death metal (Cynic, Atheist) and modern fusion prog (Exivious, Gordian Knot, The Omnific), grafting together twisted branches of instrumental aggression with smooth and jazzy chord choices in a signature double-bass (not that kind) sound. Many tracks are labyrinthine in nature, wildly transitioning from idea to idea at the drop of a hat. To glue this collage together, Quadvium bookend songs by reprising an introductory idea or reincorporating passages from earlier in a track. The fretless basses often sit at the compositional center, sometimes swirling around each other in a jousting frenzy (“Náströnd”), at other times coalescing in ethereal harmonies (“Eidolon”). The texture and sound of the bass is explored all throughout Tetradōm, often evoking in the quieter moments imagery of still, placid water gently rippling against a cosmic sea backdrop.

And like water off an astral duck’s back, Tetradōm’s ideas roll off my consciousness the moment they pass through my tetra-dome. Most tracks begin cohesively enough, then descend into chaos: pieces like “Moksha”, “Ghardus”, and “Nästrónd” introduce a melody that builds in intensity only to follow them up with a bevy of sudden, jarring transitions into unrelated ideas. As a consequence, any momentum that may have been established is halted and the revisited passages feel like separate tracks that were spliced and rearranged into a single piece. I enjoy many of the ideas that Quadvium try, particularly the jagged tech deathy fusion that opens “Apophis” and its subsequent piano break, or the tranquil floating bass of opener “Moksha”. But for the ideas to have impact, they need to offer context for a grander moment or lead to a central theme; a collage of cool moments that are bookended by a motif does not a successful song make. The production doesn’t do these pieces any favors either. The louder parts of “Moksha”, for example, are difficult to listen to as every instrument feels crunched into oblivion, none given space to breathe or any sense of prominence in the mix.

Tetradōm’s most successful songwriting appears on “Ghardus” and “Eidolon”. The former begins with a lopsided fusion drum solo that rolls into a foreboding atmosphere complete with creeping guitars and ominous, thrumming bass. This establishing idea gradually evolves across the track’s runtime, coming to a semi-climax with a pleasant guitar solo and a surprising piano break. “Ghardus” still gives the slightest nagging feeling of meandering but at least lays down a solid compositional foundation for Quadvium to explore their double-bass (still not that kind) frenzy. “Eidolon” features a breathtaking and otherworldly bass tone, swirling tides of purple ebbing and flowing in intensity to staccato rhythms and intermittent soloing. The songwriting is not quite as strong as “Ghardus”, but manages to explore its established ideas well and even includes a subtle nod to opener “Moksha” to bookend the record.

The premise of Tetradōm had me giddy with excitement, but its execution swiftly yanked me out of my suspension of disbelief. The briefest lapses in my attention left me wondering how the hell we got here, and even when listening with a laser focus, the songwriting approach is a largely inscrutable as tracks fly from idea to idea. However, it may be more helpful to see Tetradōm as a sketchbook that prototypes the possibilities of this playing style. With a bit of songwriting finesse and a continued lean into the strengths of the fretless bass, one can only hope that future Quadvium releases are a two-for-one deal worth investing in.

Recommended tracks: Eidolon, Ghardus, Apophis
You may also like: Coevality, Gordian Knot, Vipassi, Panzerballett, Barend Tromp, Exivious, Planet X
Final verdict: 4/10

Related links: Bandcamp | Spotify | Facebook | Instagram | Metal-Archives

Label: Agonia Records – Bandcamp | Facebook | Official Website

Quadvium is:
– Steve DiGiorgio (bass)
– Jeroen Paul Thesseling (bass)
– Yuma van Eekelen (drums)
– Eve (guitars)