Hola. Different recordings have different intensity at the bass or the instrument(s) that produce heavy bass or just bass in a general way of speaking. If your room is bass shy, the you can use those controls to set them up to the desire bass energy at your golden position seat. But the question here is how to use those controls. 50Hz control is for most musical instruments, and the 25Hz is for organ music. I rather have less with quality than heavy bass notes. This is my liking and not necessary yours.
The 25Hz control is of the lowest bass notes, the super deeper ones like organ. Just keep in mind that the last big concert piano musical key note is an A. The frequency response of this not is 27.5Hz. Usually this key note at the piano is not use, because even the piano itself can not reproduce it well. So there are only few musical works using this very low key note.
My advise is: put the knobs in the center position. Play your most liking music and listen to the bass player. If you think that at your golden seat, you need more, the increase only +2dB at 50Hz and listen again. If you have too much bass energy, the sense of 3D and the stage is lost. Some musical notes, if you have it too strong, will be like having the bass player next to you, and then suddenly the bass player on the other musical notes is located at the stage. Its like a cartoon.
For HT settings, use the ones that you liked most. Heavy bass is nice of booming bombs or blast.
Happy listening!
