Help with understanding receiver equalization and settings

[Brab]

I'm trying to understand what my Yamaha RX385 receiver is doing with respect to equalization. I've run the YPAO. If I understand that correctly, the YPAO corrects the frequency response, and speaker distance. I assume then, that the PEQ equalizer setting reflects the YPAO adjustment. I find that with PEQ in effect, the highs are too bright, and the bass too thin. Why is this? Things sound better with the equalizer turned off, and the receiver set to STRAIT. Shouldn't that be more or less equivalent to the DIRECT setting? But it actually seems very different. Even with PEQ off, some aspects of the YPAO seem still in effect. Is that the case? Thanks in advance for anything that would help my understanding of what the receiver is doing. I'm not at the moment looking for help in how to get the best sound. That will come later when I think I understand the receiver settings.