Your 6" Yamahas are not a neutral reference.
Studios deliberately use bad speakers (NS10s, Auratones) to check for this.
In the business it's called "translation" - a good mix sounds good on everything from earbuds to a car stereo to $$$$$$ hifi.
It's almost impossible to make a mix that translates without spending a lot of money on neutral monitors and acoustic treatment.
But there are tricks you can use to make a mix translate better. E.g. You can cut the lowest octave or two in the bass, because no one (outside of a club) can hear it anyway, and use bass sounds with plenty of mids, so you can hear the line even when the low bass isn't there.