beyers, especially older beyers like dt880 dt990 T1 have very high q peaks and dips from 6-10k, which makes these headphones terrible for eq. if you use higher Q compensations for those peaks, you have to be quite precise at the frequency, if you use low q filters, to compensate our the bright/ringingness, you will still end up with narraw peaks or dips (see amir review on dt990, there is a measurement after eq). so quite annoying experience and time consuming to get the balance right. I will never spend my time with any of the high q peaks beyers again (I experiement peq on dt880, dt990 and t1 gen 1, all has some problems even after many many peq profiles while I spent little time to get Hd800s and he6sev2 right.)