So after listening to the 8vm song a hundred times, I learned (thanks Mattheous on Discord/reddit) that the verses leading up to "trapped inside this Octavarium" is each referencing the 8 songs on the album, in order.
Ten years of listening to the album, and this is news for me. Fantastic.
Yeah, that rocks.. Also, you can hear a few seconds clip of each song on the background..
And you can hear portnoy going "first... Second.. Third etc.."
The backing vocals I have noticed, but clips? I'll have to give it another listen.
He actually says "
Root", "Second" (...) and "Octave", which was the original name for the song/album before they changed it due to its similarity with the album Octane from Spock's Beard, released earlier the same year..
About the clips, even if with some effort you can hear them all, the most listenable are The Answer Lies Within, I Walk Beside You, Panic Attack and Never Enough.. The rest I can barely hear them..