Excess group delay and mismatched phase response

[RenPa]

The distortion levels seem ok and consistent to me except for one measurement during which there was some environmental noise with around 1kHz frequency but if you are hearing pops then it's probably a more serious issue.

yes but the yellows are better (less distortion) than the blues in the bass between 20Hz and 200Hz isn't it?

 

[OCA]

Yes but not necessarily because they are lower but because they are smoother and flatter. Yellow is better than all others at 49Hz for example although it's the highest at that frequency.