Charlotte Church's transformation from child classical music star to pop singer to indie-rocker has been widely documented elsewhere and her reinvention continues on with influences drawn from a wider pool of sonic ideas than you might initially expect.

Four, the latest instalment in a series of five self-released EPs, is perhaps the most experimental out of the efforts released so far, but - as ambitious as it endeavours to be - this six-track set sometimes just ends up erring on the side of confusing.

First track 'Entanglement' explodes with rackety drums and an '80s vibe. Credit where credit's due, Church's lyrics are both mature and engaging: "Against all odds we're tangled up/Maybe every atom, maybe every proton quark and preon will meet some day/Until that day we're tangled up," she sings. The song's schizophrenic, contradictory elements, however, fail to gel well.

Poppier follow-up, 'Love Alone', lacks a real hook and comes and goes without leaving an impression even after several listens. Meanwhile, the vocodered effects on 'Little Movements' significantly detracts from what is, otherwise, one of the more grabbing cuts on the EP. Where 'Entanglement' is let down by its bits and bobs jarring with each other, 'Little Movements' manages to bring its various components together in a way that works.

Track 4 on Four is where things get a little bit more interesting, with the gorgeous 'Death and Mathematics', a mid-tempo groover that oozes finesse. Church's voice here is pensive and the production gilds it beautifully.

Penultimate cut, 'Hood Shade' starts off slow and uncertain but makes up for it by bringing in a strong bombastic chorus of "can you hear me?" at the rather tardy 2:43 mark. This could have been a good number to round off the EP but instead we get EP closer, 'Love', which sets things back somewhat. Sounding like a demo, 'Love' doesn't really add much to the mix and tails off insignificantly.

Church has described Four as futuristic driving music. "I call it cruise-wave," she is quoted saying. That in itself is not a bad way to characterise this collection of songs, which has a certain enjoyable sprawl and would make a good companion for a long wintry drive. At its highlight moments, it acts as a reminder of Church's terrific, powerful voice. At its low-points, it suffers from being too eclectic for its own good. Ideally, the singer's full length album, scheduled for this summer, will adopt a more consistent, overarching feel.