I hadn't used my Koss ESP95X much in the last couple months, mostly because I've put together a small collection of stats I'd been playing with and occasionally modifying. Most recently a Nectar Pollinator that I'd modified with better pads, headband and dust protection. After a head to head comparison, I had put my Pollinator's as my 2nd favorite stats - and my ESP95X at 4. I was debating whether to sell the ESP95X, but had been thinking for months about what might happen if I removed all the damping, and decided I had little to lose. I've loved modding headphones as a release during the pandemic.
So for 2 days I listened to the Koss ESP95X with Stock pads to re-accustom myself to them. Again - they do nothing wrong, and have a nice relaxed, airy presentation. I decided I definitely preferred the more fun/full presentation of the Nectar Pollinators. So I decided to take a risk and open up my ESP95X.
**Disclaimer - I take no responsibility for damaging your Koss stats if you try this, this mod is not reversible and likely voids your warranty. I was prepared for the possibility I might accidentally destroy my headphones. Second Disclaimer - at 43 I know I'm not too treble sensitive. My reasonable listening maxes out between 14-15 Khz.
I removed the headband first, and the pads. Under the pads is a stick on filter, that's pretty thick. I'd previously removed it alone - as I'd reported previously with some improvement in resolution. BUT taking it off requires patience, and it definitely tears as you pull it. I had to be careful not to accidentally put a finger through the dust protection underneath, nor the driver.
Once the filter was off, I had to undo 4 screws and expose the driver/stators/dust protection which are bound together in one assembly I did not disturb. I pulled the whole assembly by lifting up at the cable strain relief, paying attention to how the headphone cable is slotted in. The driver assembly pulls straight up if you have the headphones laying flat.
Behind the driver assembly is a thick sheet of paper - that I figured would make little difference sonically, but I was wrong. It connects to the grill at 4 points with 4 spots of glue. I carefully pried those 4 spots with a tiny screw driver so as not to tear the paper. I was relatively successful - but the paper now has 4 circular holes and I don't think it would be easy to replace.
After that - I just reassembled. At first I considered whether I would replace the thick filter paper with speaker cloth for added dust protection - but I don't think I will. Connected the way it was, at just 4 points - it didn't offer great dust protection to begin with.
To make a long story short - listening afterwards was a night and day difference in clarity and microdetail. I feel these are MUCH faster and more resolving now, among the best I've heard. But they were very fatiguing with the stock pads, and sibilant as well. I tried my thin Vesper leather pads, and had much the same experience. Finally - I tried my perforated Dekoni leather pads, added a sheet of speaker cloth over the dust protection on the pad side, and the sibilance and fatigue went away. I've listened 4 hours straight at a sitting. Though I usually prefer solid leather on the outside - I've found that perforated leather or pleather inside pads goes a long way towards killing sibilance and reflections.
I then compared my ESP95X and Pollinators for 3 hours connected to my Stax SRM 717 amp. They both played at the same time, and I was switching between the Pollinators and the Koss often during songs. It's quite obvious the Koss were less congested and picked up every detail, where the Pollinators suddenly seemed slightly "hollow" by comparison. The Koss did seem to lose some sound stage, the mids were more intimate. But to me, classical music and female vocals never sounded so good. The bass quantity was still much lower on the Koss versus the Pollinators. The Pollinators have bass I could FEEL in my chest - and for the same notes, I could only HEAR it on the Koss. The bass was very resolving and layered on the Koss, just not a lot of quantity. I used a tone generator at my regular listening volume - and could hear down to 20 Hz, but the slam of the bass just wasn't there.
Right now the Koss ESP95X without damping are my 2nd favorite headphones, and I'm dying to do another head to head with my Stax L700's. The only reason I haven't done so is that I disassembled the L700's to design better yokes. I ordered the hopefully upgraded yokes - but due to the recent weather, they've been stuck at Fedex for over a week. I'm hoping they'll get here by the coming weekend.
One last note - I previously sent my Koss ESP95X for warranty repair, since my right driver suddenly had a huge imbalance. They came back repaired. When I took them apart - the repaired right driver was clean, but the left driver had white dust between the dust protection and the filter paper? I wonder if that dust might be from construction - and can cause the buzzing some people have heard? In my case I just blew out the dust - and have had no issues. *crosses fingers* But again - getting to the driver assembly probably voids your warranty, so please proceed with caution.
