Is your bass guitar disappearing into an abyss of muck? Hard to make out the notes? Hard to even know the bass is even there? There are many factors, sometimes the main ones being the instrument and the player, but that’s another topic… Another very common factor is that there may be too much low end swimming around in the mix for the bass to make it though. Fix that by rolling off the low end on EVERYTHING that is not the bass or the kick (or whatever low end instrument in your mix that needs it’s own space). The first tool to grab is the high-pass filter, common to most eqs. High-pass filters remove low-end rumble that has no business being there. Guitars, vocals, and most of the drum mics don’t need to be passing such low frequencies. Roll off the low end until you hear it start to negatively impact the vocal or instrument, and then back it off just a bit. You may also need to do additional low end adjustments in addition to the high pass filter.
Not rolling off the low end on these tracks results in an out of control high-bass/low midrange buildup. Aside from making the mix murky, they make it very difficult for the bass to sound good. Proper cleanup of low end on every track will go a long way to solve this.