Let me know if you can replicate this, Only do this from 10 to 150hz:
1. Open up an EQ
2. Open up an operator (click the box fixed, in between the Fine and Level in A)
3. Set level of playback (Volume of operator to -8db) and volume of DAC to speaking volume according to 260 to 300hz
4. Slowly sweep up from 10hz and put in nodes where you hear volume changes
5. Adjust notes opposite of volume changes so that it sound like 1 consistent volume
6. Open up Goodhertz Can opener. Set to Hyper realistic
Test references for low end and your own music in your most frequented listening spot (car, earpods etc). If you notice a song with too much low end can you tell it has too much low end after the headphone hack?