I was thinking of something like this for some time, and I had to do it eventually. I'm not looking for weekly/daily releases here
This is very good said from my most trusted tested
@aceedburn 
Thanks for others who helped test anything too, of course!
There is certainly more presence in the lows area.
This firmware made me realize how much I like a good warm sound signature. Some bass guitar can literally make me think of the word "delicious" especially with the Sony Z7M2, but also with the Beyerdynamic DT1770 Pro - the latter are brighter than the Z7M2, and the warmness definitely helps, with detailed highs still being there no problem.