Oh, ok, that's good! (I've checked and you've entered the filters correctly.) What device are you listening on? You just got the headphones plugged directly into a laptop/notebook or something? You'd want to make sure you Windows volume is at 100% if it's not loud enough. Negative Preamp you should probably leave on -5dB, but if you still don't have enough volume you could just rely on the clipping detection meter in PEACE - so you'd click the "prevent clipping" box that you can see in the bottom of your screenshot and just leave have the Negative Preamp at 0dB - but there will be definitely times that it will clip at which point it will decide on it's own Negative Preamp to use automatically, but that's a way of maintaining maximum volume whilst protecting yourself from clipping.
Re bass for your own taste, just change the dB Gain of Filter #1, so the 20Hz filter. Instead though you could add another filter, Low Shelf at 105Hz, Q0.71, then have your dB plus for increasing bass or negative for decreasing bass. The Low Shelf Filter at 105Hz will make greater changes to the bass level, so if you want to do that you'd add one more filter to what you currently have, and you'd leave Filter #1 (20Hz) as it is currently without changing it. But you could try either approach, first it's easier to try changing filter #1 (20Hz), but if you find it's not having enough effect, then return 20Hz filter to what you have right now, and then try the Low Shelf 105Hz filter I mentioned.