My computer is using HQPlayer to send DSD files (including PCM files converted on-the-fly to DSD) to the Schiit Loki DAC, then the Vali amp, and on to my HE-300s. Like many posters, I consider the HE-300s to be a major bargain at $150. I ran everything in stock configuration for a few weeks and liked the setup just fine.
Then I read about this mod, removing the felt. I did it. When I examined the felt, I certainly theorized that removing it would be a good thing. Earlier posts to the effect of "No one would ever make speaker grills from this stuff" seemed spot-on to me.
I plugged everything back in and fired it up. The results were severely disappointing. I spent many hours listening and my initial inpressions were borne out - unwelcome sibilance, excess brightness and harshness. I found listening sessions substantially more fatiguing, much more quickly. Nevertheless, I ran this set-up for nearly a month, listening for hours every day.
Now I've put the felt back in. The harshness is gone. I can listen for longer without tiring. What's really odd is that I am satisfied with the volume knob turned up less when the felt is present.
Maybe my ears are weird. Maybe I just prefer a much darker overall sound than most folks. Maybe I listen to crappy music that's recorded harshly and the darkenss of this setup is euphonically camaflouging upstream problems. However, I don't think so. I have some beautifully recorded DSD files of classical music that I like better, too, with the 'phones in their stock configuration.
Whatever the reason, I found this mod to be severely counter-productive for me.
I agree. My setup is very simple compared to yours, running the modded HE-300 through a FiiO E07K, but I also ended up fatigued after 30-60 mins of use. I did like some aspects of it, like the perception of a wider soundstage and a tad more clarity, but the harshness gave me headaches. I have to admit that I do personally prefer darker tones due to my sensitivity to sibilance, though. Grado lovers might find it more to their liking.
All in all, I'm very happy with the sound coming from the stock HE-300.
Edited by Kakuz - 1/1/14 at 2:52pm