Have a look at EQIf I found added warmth beautiful (I don't know yet)
You can use this to "tune" any headphone.
To much bass, just EQ a couple of dB's off (although Sennheiser is consider bass shy, I always do as I do think the bass to pronounced for classical)
Need warmth? A slight emphasize of the mids will do (even better, leave them as they are and lower the rest to is avoids clipping).
As I'm on Win & Android, can't advice you on OSX but maybe this one gets you started.
Applying an equalizer in macOS allows you to take control of your audio playback. Learn these six ways to apply an equalizer in macOS.