Toob much Bass

Is there a way to attenuate the bass on the HT280 headphones?  Everyone on TV sounds like they are talking with marbles in their mouth.  My previous set of headphones sounded great.  These, not so much.  I have tried the optical and RCA plug connections: they sound the same; though optical has about half the volume of RCA.  i have tried the headphone with and without my hearing aids, to no satisfaction.  Attenuating bass or amplifying treble might do the trick.

[AvantreeOfficial]

This model is not the best with Bass. Can you return this set and exchange for model "Opera"? That is actually much better with voice clarity.