Mastodon had been gradually evolving towards a more accessible sound over the years, so many people expected their new album, 'Once More 'Round the Sun,' to step over the line, beyond which lies the mainstream. Well, the Gerogia-based band's new release isn't its 'Black Album' at all. And it seems the reason is that Mastodon just can't simplify their songs enough to give them an 'arena' sound.

So what? They missed a chance to be played at every wedding for the next 30 years? But what did they achieve with 'Once More 'Round the Sun?' This is the album where Mastodon find just the right balance between complexity, substance and accessibility, in a way that is not unlike the approach of one of their biggest influences – Rush.

Yes, songs like the first single 'High Road' and the title track are almost the type of radio-friendly rock you can nod and sing along to. 'Aunt Lisa' even fades out to chants of 'Hey ho, let's fucking go...' that relate to you know exactly what. But a similar, seemingly pop-sensitive sound, is just one of the things Mastodon offer in this album.

Take opener 'Tread Lightly' for example. It starts with an intro of strumming guitars that the band turns into a foggy groove that follows their pulsation, and as the ever intensifying riffs and Brann Dailor's signature, fill-heavy, style of drumming create a swirl, the songs multi-voice chorus takes a leap above it, only to come back down with a shredding solo. It's not the kind of track they play on the radio.

Even the album's more straightforward moments feature music that is so dense, that you feel like your senses are constantly unaware of some of it. Guitar melodies echo like an eerie presence all over the album, and the beginning and end of 'Chimes at Midnight' are among the rare moments when they take center stage. The rest of this song, however, turns out to be among the heaviest, and closest to 'Remission' things the band has done lately.

In a way, this is probably Mastodon's first album, where the change in sound is so delicate, that the differences are fewer than the resemblances. It's neither revolutionary, neither stale – it just 'a Mastodon record.' At this point of its career, this band maybe doesn't need to reinvent itself anymore, but instead should stick to its strengths. A lot of other bands would sell their souls to have the same strengths.