[emergencylies]

Hi,
 
I was reading this article at Innerfidelity, http://www.innerfidelity.com/content/reducing-headphone-treble-response-paper-filters-front-driver#VOJ6iPW4DqksG21p.97 , where Tyll talks about using surgical masks to reduce frequencies greater than 5k.
 
Since I'm not really clear what part of the surgical mask he's referring too, I was wondering if there are any other materials that are specific to 5k+, or even 7k+ that you can put in front of a driver to reduce the treble response.
 
Thanks!

 

[emergencylies]

I'm actually looking to reduce the upper upper mids, like 1.5-4k, so if anyone knows good materials or mods to do that (mdr-z7), I'd be indebted.

 

[HiGHFLYiN9]

I've used PartsExpress speaker grill fabric to reduce listening fatigue on a pair of Koss, which usually occurs for me in the upper midrange. 
 
https://www.parts-express.com/parts-express-speaker-grill-cloth-black-yard-70-wide--260-335
 
7 bucks