Flg2001: I agree with Xlr8or (based on what you said re: balance toward high frequency) and therefore want to revise my original recommendations.
I would start lower, maybe as low as 40 ohms or sufficiently low to hear "enough-but-poor-quality-bass." "Enough" means loud enough. "Poor quality" means boomy, muddy, bloated. Then add resistance just 10 ohms at a time (because your range from lowest to highest is so small) until the bass tightens up but still maintains good volume level. That's where you want to be.
I would start lower, maybe as low as 40 ohms or sufficiently low to hear "enough-but-poor-quality-bass." "Enough" means loud enough. "Poor quality" means boomy, muddy, bloated. Then add resistance just 10 ohms at a time (because your range from lowest to highest is so small) until the bass tightens up but still maintains good volume level. That's where you want to be.