How to boost mids/add warmth?

[BCool]

I've built my first pair of DIY closed back headphones from parts sourced from aliexpress and it's turned out OK. The sound signature has turned out bright with fairly linear and detailed bass, but the only problem is that the region between ~300Hz to ~800Hz (lower mids? mids? upper bass? not sure what this region is called) is a fairly scooped out.

Is there a way to boost this region with mods? I know that you can boost bass by playing around with the baffle and the back volume, and that you can reduce treble by putting materials in front of the driver, but I haven't found how to add warmth to headphones (other than running them through a tube amp haha).

Any help would be appreciated, thanks.

 

[Darksoul]

I'm my previous experience with doing simple mods and tinkering. What added the most warmth is earpass, thick leather earpads made headphones warmer. In closed backs, I've noticed that making sure there's proper seal between the cup and the driver add a lot of warmth as well. To deal with brightness dampening material inside the cup, dampening the driver also helps somewhat.

 

[BCool]

Thanks!
I'll order some new pads but in the mean time I'll play around with toning down the brightness. I might also put holes in the driver baffle, I have a feeling that might bring up the low end but I'm not sure how much that will extend into the mids.