As bands change line-ups, it becomes hard to retain an original sound.

For Australian hard-rock band Wolfmother, its new album sounds a lot like its previous efforts, leaving the listener ambivalent.

Although guitarist and vocalist Andrew Stockdale, the only remaining original member, has surrounded himself with new musicians that allow him a greater degree of creative freedom.

However, the band's latest effort, titled "Cosmic Egg," quickly turns from rock music returning back to its psychedelic roots to a record on loop.

This is not necessarily a bad thing. The album consists mostly of low-end riffs and Stockdale's falsetto vocals with sloppy Led Zeppelin-style guitar solos.

Speaking of the iconic rock band, Stockdale deserves a lot of praise for his remarkable ability to mimic Zeppelin's two driving forces -- singer Robert Plant and guitarist Jimmy Page -- balancing the climbing timbre of his vocals with the bellowing depth of his guitar riffs. However, regardless of this talent, there is really only so much he can do to impress before listeners feel the need to move on to something else.

In short, "Cosmic Egg" is not a bad album, but even with the new musicians surrounding him, Stockdale has simply fallen into the trap of giving too much of the same on a sophomore album.

Without this sense of difference, the album becomes boring.

Why buy the new album when you can just just as easily put on the old stuff?

And the tracks follow suit.

The title track and the song "Phoenix" follow a formula easy to figure out -- guitar riff starts it off, the drums come in for a few bars, play through the verse to a crescendo in the chorus, then a fuzzy guitar solo.

For all the criticism about the lack of differentiation, the band seems to have improved musically.

One can hear this example of growth from the last album, in which the band seemed to be doing mere impressions of '70s rock bands.

Now, it's finally combined these influences and patented them as the band's own property.

Unfortunately, this is not good enough if the band wants to grow.

It's disappointing that the glimmering examples of this musical experimentation burn out before they can be fully explored.

"In the Morning" shows Stockdale's proficiency through finger-picking a riff on guitar instead of going for trademark low-single note riffs present on the other songs.

Another example of this is when the guitar fades away on "Far Away" and a piano can be heard playing through scales at blinding speed.

But as soon as one becomes impressed, two lightly played chords cause the greatest part of the song to dissipate.

In the end, this vision of brilliance is only 14 seconds long.

As soon as this is over, we get the same old bending one-note riffs when the album moves onto its next song, "Pilgrim."

Whether this is because of Stockdale's lack of understanding about his tracks or just mere laziness remains uncertain.

"Cosmic Egg," if one listens to it all the way through, is a decent follow-up.

But it deserved to be better. If Wolfmother wanted to rock, they succeeded.

But, just like a rock, the album is unable to change its shape.

Grade: C+

Download: "In the Morning," "Far Away"