[BigBig5]

I have a pair of HD668B that I modded some.
Mods:

• Added electrical table inside the cups covering the holes. This lowers the sound stage but not too much and helps control the sound.
• Removed paper inserts in the cups because not needed with 1st mod
• Removed foam inserts. Clears up the sound, helps to tame the treble somewhat, and also, bringing the mids forward.
• Replaced stock earpads with Tranesca leather Angled big overear earpads. This gives comfort over the cheap stock pads
• Resoldered the poorly done wires for a better lasting connection.

I ordered some BRAINWAVZ XL PU leather to replace my recently peeling earpads but hasn't arrived yet. I notice with some EDM songs but not all can have hot/harsh treble if mids/lows aren't playing at the same time. In foobar2000 I used to set EQ to help bring down treble some. Now I don't want to rely on an EQ because I use multiple devices and OS's to listen to music. What materials for DIY inserts should I use that would help with treble? I have heard of using coffee filters but that has different results depending on the model of headphones. Also, I don't have the foam inserts anymore.