Volume adjustments new system!!

[musickid]

For the past 3 years i have been using an akg 550 with a yulong usb 100 amp/dac. this was simply a matter of plug in and wrank up to high volume and go. very simple. i recently upraged my system to a earmax pro 2 amp, b and o h6 cans and a modimultibit bit dac. initially being the amateur i am i thought that the operation would be along the same lines as the previous set up. how wrong i was. this is a much subtler, sensitive, yet potentially just as powerful set up. after 6 hours of listening here is what i found. on tracks that are not bass heavy or bass 'orientated' such as opera vocals, madness or twist in my sobriety by tanita tikaram the sound is really beautifully liquid and smooth. on bassy track however such as maria maria santana i found at higher volumes the sound became muffly and the bass verging on slight distortion. not very pleasant. after a while i found if i kept the volume on the earmax fixed on 9 o'clock (it starts around 4 am if that makes sense) for all tracks, and kept the volume on tidal at max for the non bassy tracks, i would only then need to lower the tidal volume to between 80-60 percent on the scale to more or less eliminate the rough edge on the bass music.

is this kind of adjustment normal on such systems and is there anything else i can do to improve this? should i allow more time for the headphone and system to burn. so far only 6-7 hours useage. the muffled bass occured with both the h and o h6 and the akg550 cans. both low resistance cans for which this amp handles very well as stated by the manufacturer. finally would something like amarra for tidal help me fine tune a nicer end sound free of any distortion at higher volumes? many thanks to all