[hayerjoe]

thanks for all your comments. I really should have said in my initial post that the 33ohm speakers are already attached and sound fantastic, and certainly NOT underpowered

Not quite sure what to do now, the general consensus would seem to be they should be ok left as-is, but kalee20's idea seems absolutely safe unless resistors in parallel really do lower the speaker volume too far

The speakers had no manufacturer mentioned at all, 33ohm is indeed a strange value, any ideas who made such things and what advantage they provided?