While this model features a Celestion BN12-300S, we actually don't recommend the BlockDock 12HD for bass. Here's why:
Typically bass speakers are put into a bass cabinet and because of the design of the cabinet it prevents the speaker from over-excursion. The 12HD is intended as a guitar cabinet so you can't go too far and damage it.
That being said, you technically can use it with a bass. Light duty use should be okay. But only very low power.
If you're looking for a bass cabinet, we'd strongly suggest trying out the BassDock 10/12