Here is a link to the specs of those polk towers.
Although they are rated to play flat down to 30hz the built in crossover is fixed at 700hz. Most subwoofers play only from slightly below 20hz
up to 80hz. 18hz to 700hz in any one driver is not good. Too wide of range. For stereo music just the 2 towers would be fine.
Almost all receivers have a mid/bass crossover switch. That switch is engaged by setting speakers to small so don't freak out.
And they all make you physically change from large to small after running ypao/audyssey etc. every time. Part of the problem is
that receiver only has one global crossover for all speakers so if the fronts are set to low crossover so are the other speakers.
And you have a subwoofer so use it. The fronts can be set to large (full range) and the others to small with the crossover active on only
those and there is an extra bass control setting in there somewhere. That will send the deep bass to the fronts and subwoofer.
Go ahead and try all options and find the preferred output. Page 83 of the manual covers these settings found inside configuration.
Ideally I would set the front crossover to 40hz, center to 80hz and the surrounds to 90hz or above.
Yamaha only offers non-global crossovers on the highest models 2020/3020.
Your tower has a fourth driver that is a tweeter crossed at 20khz and above. That is a dog whistle.