Octobans might sound different depending on what material they're made of. For instance, Pearl's octobans ("Quarter toms") are made of aluminum and Odery octobans are made of pine woods. Listen to this clip, it's an Odery octoban together with an Odery gong bass drum:
Octobans get their pitch from the length of the drum. The sound sort of resembles a conga played with a stick.
To get more ideas of what octobans are all about, listen to solos from Mike Portnoy and Simon Phillips. They use octobans a lot!