From the description given it sounds like the bass is dry. You may want to try a small amount of ambient room to the bass track to help pull it back with the other instruments.
If it's a sound quality issue, EQ, strings, the DI or preamp you are using etc. all make up components of the final recorded sound.
Again, without knowing what sound you are shooting for it's difficult to prescribe a remedy. Do you want your bass to sound like Korn, Bootsy Collins, Jaco, James Jamerson, Entwhistle ...